Add specs for Thread.each_caller_location

[AI-Mozi]

#1016
[Feature #16663]

Thread.each_caller_location is added.

[AI-Mozi]

What else is worth testing?
Also I'm not sure if these test cases meaningful enough.

[andrykonchin]

What cases I would consider:

• it iterates through the current execution stack
  • we can check e.g. that every yielded value is instance of Thread::Backtrace::Location
  • and that all the yielded locations equal exactly what #caller_locations returns
• it raises LocalJumpError when called without a block
• it doesn't accept positional and keyword arguments
• it returns nil
• it raises StopIteration at the end when used as an external enumerator (there is such test case already)

There are two more cases mentioned in the https://bugs.ruby-lang.org/issues/16663:

• break stops the iteration
• using to_enum (Thread.to_enum(:each_caller_location)) doesn't add any locations related to to_enum implementation, so locations should be the same as Thread.each_caller_location {} returns.

Maybe it also makes sense to add a similar test case:
https://github.com/ruby/spec/blob/d59824930da3522aad8d3edf0e146a4f4f595533/core/kernel/caller_spec.rb#L59C4-L69

There is a WIP PR in TruffleRuby oracle/truffleruby#3050 that contains some specs but I think this PR can be merged independently if there are more detailed test cases.

[AI-Mozi]

Maybe it also makes sense to add a similar test case:
https://github.com/ruby/spec/blob/d59824930da3522aad8d3edf0e146a4f4f595533/core/kernel/caller_spec.rb#L59C4-L69

How would you see implementations of this test because I have no idea 😅?

[andrykonchin]

Thank you!

[AI-Mozi]

Thank you too, it was a tough one 😅