Add example showing load_iseq interaction

[jez]

Motivation

❯ cd gems/sorbet-runtime
❯ ./run.sh
-- before require --
-- forcing LAZY_CONSTANT! --
LAZY_CONSTANT=0
-- before Example.main --
/Users/jez/stripe/sorbet/gems/sorbet-runtime/lib/types/_types.rb:222:in `must': Passed `nil` into T.must (T::MustTypeError)

    T.must(nil)
           ^^^
        from /Users/jez/stripe/sorbet/gems/sorbet-runtime/example_untransformed.rb:5:in `main'
        from entry.rb:20:in `<main>'


^unpatched ---------- patched:


-- before require --
-- transformed_src for path=/Users/jez/stripe/sorbet/gems/sorbet-runtime/example_untransformed.rb --
module Example
  autoload :LAZY_CONSTANT, '/Users/jez/stripe/sorbet/gems/sorbet-runtime/example_transformed.rb'

  def self.main
    T.must(nil)
  end
end
-----
-- forcing LAZY_CONSTANT! --
LAZY_CONSTANT=0
-- before Example.main --
/Users/jez/stripe/sorbet/gems/sorbet-runtime/lib/types/_types.rb:222:in `must': Passed `nil` into T.must (T::MustTypeError)

    T.must(nil)
    ^
        from /Users/jez/stripe/sorbet/gems/sorbet-runtime/example_untransformed.rb:5:in `main'
        from entry.rb:20:in `<main>'

Test plan

See included automated tests.

[jez]

Interestingly, this does not affect the monkey patch for NameError, which seems to turn itself off in this case:

❯ bundle exec ruby dne_entry.rb; echo $'\n\n^unpatched ---------- patched:\n\n'; PATCH_LOAD_ISEQ=1 bundle exec ruby dne_entry.rb
-- before require --
-- forcing LAZY_CONSTANT! --
LAZY_CONSTANT=0
-- before DNE.main --
/Users/jez/stripe/sorbet/gems/sorbet-runtime/dne_untransformed.rb:5:in `main': uninitialized constant Integer::DoesNotExist (NameError)

    Integer::DoesNotExist
           ^^^^^^^^^^^^^^
        from dne_entry.rb:20:in `<main>'


^unpatched ---------- patched:


-- before require --
-- transformed_src for path=/Users/jez/stripe/sorbet/gems/sorbet-runtime/dne_untransformed.rb --
module DNE
  autoload :LAZY_CONSTANT, '/Users/jez/stripe/sorbet/gems/sorbet-runtime/dne_transformed.rb'

  def self.main
    Integer::DoesNotExist
  end
end
-----
-- forcing LAZY_CONSTANT! --
LAZY_CONSTANT=0
-- before DNE.main --
/Users/jez/stripe/sorbet/gems/sorbet-runtime/dne_untransformed.rb:5:in `main': uninitialized constant Integer::DoesNotExist (NameError)
        from dne_entry.rb:20:in `<main>'