[WIP] Update vendored mspec in spec-runner

[lopopolo]

• Branched from artichoke/mspec@d28418b
• As of artichoke/mspec@a1cad28

Proposed tree: https://github.com/artichoke/mspec/tree/artichoke-vendor-proposed-gh-2189

Status

Blocked on Hash#compare_by_identity not being implemented.

$ bundle exec rake spec
cargo run -q -- enforced-specs.toml
Traceback (most recent call last):
        8: from /artichoke/virtual_root/src/lib/spec_runner.rb:48
        7: from /artichoke/virtual_root/src/lib/spec_runner.rb:48:in require
        6: from /artichoke/virtual_root/src/lib/mspec.rb:2
        5: from /artichoke/virtual_root/src/lib/mspec.rb:2:in require
        4: from /artichoke/virtual_root/src/lib/mspec/matchers.rb:31
        3: from /artichoke/virtual_root/src/lib/mspec/matchers.rb:31:in require
        2: from /artichoke/virtual_root/src/lib/mspec/matchers/raise_error.rb:1
/artichoke/virtual_root/src/lib/mspec/matchers/raise_error.rb:2: undefined method 'compare_by_identity' (NoMethodError)
NoMethodError (undefined method 'compare_by_identity')
rake aborted!
Command failed with status (1): [cargo run -q -- enforced-specs.toml...]
/Users/lopopolo/dev/artichoke/artichoke/Rakefile:132:in `block (2 levels) in <top (required)>'
/Users/lopopolo/dev/artichoke/artichoke/Rakefile:131:in `chdir'
/Users/lopopolo/dev/artichoke/artichoke/Rakefile:131:in `block in <top (required)>'
/usr/local/var/rbenv/versions/3.1.2/bin/bundle:25:in `load'
/usr/local/var/rbenv/versions/3.1.2/bin/bundle:25:in `<main>'
Tasks: TOP => spec
(See full trace by running task with --trace)

[lopopolo]

link:

• Update vendored reference ruby implementation #2187

[lopopolo]

This PR is blocking #2263.