Add Bundler.with_unbundled_env to RSpec.shared_context 'isolated environment'

[AlexWayfer]

It's more correct. And without it there are errors, like about yard gem:

> bundle exec rspec

...
/home/alex/.rbenv/versions/3.3.0/lib/ruby/3.3.0/bundler/definition.rb:570:in `materialize': Could not find yard-0.9.34 in locally installed gems (Bundler::GemNotFound)
	from /home/alex/.rbenv/versions/3.3.0/lib/ruby/3.3.0/bundler/definition.rb:203:in `specs'
	from /home/alex/.rbenv/versions/3.3.0/lib/ruby/3.3.0/bundler/definition.rb:270:in `specs_for'
...

There are some incompatibilities, but they can be resolved.

---

Basically, I couldn't run specs from "the cold start".

---

Before submitting the PR make sure the following are checked:

• The PR relates to only one subject with a clear title and description in grammatically correct, complete sentences.
• Wrote good commit messages.
• Commit message starts with [Fix #issue-number] (if the related issue exists).
• Feature branch is up-to-date with master (if not - rebase it).
• Squashed related commits together.
• Added tests.
• Ran bundle exec rake default. It executes all tests and runs RuboCop on its own code.
• Added an entry (file) to the changelog folder named {change_type}_{change_description}.md if the new code introduces user-observable changes. See changelog entry format for details.

[AlexWayfer]

Without this CLI returns "can't open file Gemfile.lock", I don't know why.

[AlexWayfer]

I was trying to move create_empty_file('Gemfile') into "isolated environment", but it breaks more than helps.

[AlexWayfer]

Please, help me with this, I don't understand:

> bundle exec rspec spec/rubocop/cli/auto_gen_config_spec.rb

Randomized with seed 43534
...................F.F...........................

Failures:

  1) RuboCop::CLI --auto-gen-config --auto-gen-config when .rubocop.yml contains a single line inherit_from in an ERB conditional overwrites an existing todo file
     Got 3 failures from failure aggregation block.
     Shared Example Group: "overwrites todo file" called from ./spec/rubocop/cli/auto_gen_config_spec.rb:352
     # ./spec/support/cli_spec_behavior.rb:26:in `block (2 levels) in <top (required)>'
     # ./lib/rubocop/rspec/shared_contexts.rb:46:in `block (2 levels) in <top (required)>'
     # ./lib/rubocop/rspec/shared_contexts.rb:30:in `block (5 levels) in <top (required)>'
     # ./lib/rubocop/rspec/shared_contexts.rb:30:in `chdir'
     # ./lib/rubocop/rspec/shared_contexts.rb:30:in `block (4 levels) in <top (required)>'
     # ./lib/rubocop/rspec/shared_contexts.rb:8:in `block (3 levels) in <top (required)>'
     # ./lib/rubocop/rspec/shared_contexts.rb:7:in `block (2 levels) in <top (required)>'

     1.1) Failure/Error:
            expect(File.readlines('.rubocop_todo.yml')[8..].map(&:chomp))
              .to eq(['# Offense count: 1',
                      '# This cop supports safe autocorrection (--autocorrect).',
                      '# Configuration parameters: AllowForAlignment, ' \
                      'EnforcedStyleForExponentOperator, EnforcedStyleForRationalLiterals.',
                      '# SupportedStylesForExponentOperator: space, no_space',
                      '# SupportedStylesForRationalLiterals: space, no_space',
                      'Layout/SpaceAroundOperators:',
                      '  Exclude:',
                      "    - 'example1.rb'",
          
            expected: ["# Offense count: 1", "# This cop supports safe autocorrection (--autocorrect).", "# Configuration p...reCopDirectives, AllowedPatterns.", "# URISchemes: http, https", "Layout/LineLength:", "  Max: 125"]
                 got: ["# Offense count: 1", "# This cop supports safe autocorrection (--autocorrect).", "# Configuration p...reCopDirectives, AllowedPatterns.", "# URISchemes: http, https", "Layout/LineLength:", "  Max: 125"]
          
            (compared using ==)
          # ./spec/rubocop/cli/auto_gen_config_spec.rb:309:in `block (5 levels) in <top (required)>'

     1.2) Failure/Error: expect(File.readlines('.rubocop.yml').map(&:chomp)).to eq(code)
          
            expected: ["<% if ENV[\"HZPKCEAXTFQLOWB\"] %>", "inherit_from: .rubocop_todo.yml", "<% end %>"]
                 got: ["<% if ENV[\"HZPKCEAXTFQLOWB\"] %>", "inherit_from: .rubocop_todo.yml", "", "<% end %>"]
          
            (compared using ==)
          # ./spec/rubocop/cli/auto_gen_config_spec.rb:335:in `block (5 levels) in <top (required)>'

     1.3) Failure/Error: expect(new_cli.run(['example1.rb'])).to eq(0)
          
            expected: 0
                 got: 1
          
            (compared using ==)
          # ./spec/rubocop/cli/auto_gen_config_spec.rb:340:in `block (5 levels) in <top (required)>'

  2) RuboCop::CLI --auto-gen-config --auto-gen-config when .rubocop.yml contains a multiline inherit_from in an ERB conditional overwrites an existing todo file
     Got 3 failures from failure aggregation block.
     Shared Example Group: "overwrites todo file" called from ./spec/rubocop/cli/auto_gen_config_spec.rb:358
     # ./spec/support/cli_spec_behavior.rb:26:in `block (2 levels) in <top (required)>'
     # ./lib/rubocop/rspec/shared_contexts.rb:46:in `block (2 levels) in <top (required)>'
     # ./lib/rubocop/rspec/shared_contexts.rb:30:in `block (5 levels) in <top (required)>'
     # ./lib/rubocop/rspec/shared_contexts.rb:30:in `chdir'
     # ./lib/rubocop/rspec/shared_contexts.rb:30:in `block (4 levels) in <top (required)>'
     # ./lib/rubocop/rspec/shared_contexts.rb:8:in `block (3 levels) in <top (required)>'
     # ./lib/rubocop/rspec/shared_contexts.rb:7:in `block (2 levels) in <top (required)>'

     2.1) Failure/Error:
            expect(File.readlines('.rubocop_todo.yml')[8..].map(&:chomp))
              .to eq(['# Offense count: 1',
                      '# This cop supports safe autocorrection (--autocorrect).',
                      '# Configuration parameters: AllowForAlignment, ' \
                      'EnforcedStyleForExponentOperator, EnforcedStyleForRationalLiterals.',
                      '# SupportedStylesForExponentOperator: space, no_space',
                      '# SupportedStylesForRationalLiterals: space, no_space',
                      'Layout/SpaceAroundOperators:',
                      '  Exclude:',
                      "    - 'example1.rb'",
          
            expected: ["# Offense count: 1", "# This cop supports safe autocorrection (--autocorrect).", "# Configuration p...reCopDirectives, AllowedPatterns.", "# URISchemes: http, https", "Layout/LineLength:", "  Max: 125"]
                 got: ["# Offense count: 1", "# This cop supports safe autocorrection (--autocorrect).", "# Configuration p...reCopDirectives, AllowedPatterns.", "# URISchemes: http, https", "Layout/LineLength:", "  Max: 125"]
          
            (compared using ==)
          # ./spec/rubocop/cli/auto_gen_config_spec.rb:309:in `block (5 levels) in <top (required)>'

     2.2) Failure/Error: expect(File.readlines('.rubocop.yml').map(&:chomp)).to eq(code)
          
            expected: ["<% if ENV[\"HZPKCEAXTFQLOWB\"] %>", "inherit_from:", "  - .rubocop_todo.yml", "  - other.yml", "<% end %>"]
                 got: ["<% if ENV[\"HZPKCEAXTFQLOWB\"] %>", "inherit_from: .rubocop_todo.yml", "", "<% end %>"]
          
            (compared using ==)
          # ./spec/rubocop/cli/auto_gen_config_spec.rb:335:in `block (5 levels) in <top (required)>'

     2.3) Failure/Error: expect(new_cli.run(['example1.rb'])).to eq(0)
          
            expected: 0
                 got: 1
          
            (compared using ==)
          # ./spec/rubocop/cli/auto_gen_config_spec.rb:340:in `block (5 levels) in <top (required)>'

Finished in 6.22 seconds (files took 1.29 seconds to load)
49 examples, 2 failures

Failed examples:

rspec ./spec/rubocop/cli/auto_gen_config_spec.rb[1:1:11:1] # RuboCop::CLI --auto-gen-config --auto-gen-config when .rubocop.yml contains a single line inherit_from in an ERB conditional overwrites an existing todo file
rspec ./spec/rubocop/cli/auto_gen_config_spec.rb[1:1:12:1] # RuboCop::CLI --auto-gen-config --auto-gen-config when .rubocop.yml contains a multiline inherit_from in an ERB conditional overwrites an existing todo file

Randomized with seed 43534

[AlexWayfer]

And I see fails from spec/rubocop/cli/options_spec.rb in CI, but can't reproduce them.