(locals) gracefully handle binding error when on a Fiber

[waltjones]

Description of the change

Background

TracePoint#binding cannot be called from a Fiber, though I haven't seen anywhere that this is documented. This can be confirmed by reviewing the location where the exception is raised in Ruby:
https://github.com/ruby/ruby/blob/744d17ff6c33b09334508e8110007ea2a82252f5/vm.c#L1240

And of course it can be confirmed by calling binding while on a Fiber. The above exception will be produced.

In the reported issue, the error happens when next is called on an Enumerator instance. Calling next causes execution to switch to a Fiber.
https://github.com/ice-cube-ruby/ice_cube/blob/2cdfdbaf75bd809831df1af3f0e96639bbc69ee6/lib/ice_cube/schedule.rb#L217

When local variable capture is enabled in rollbar-gem, the stack frames within the Fiber context are captured. The reported issue happens because TracePoint#binding is called while capturing these frames.

Fix

This PR rescues the failed attempt to get the binding and returns nil. Later when building the payload, it skips insertion of locals for frames where the binding is missing.

Type of change

• Bug fix (non-breaking change that fixes an issue)

Related issues

Fixes: #1094

Development

• Lint rules pass locally
• The code changed/added as part of this pull request has been covered with tests
• All tests related to the changed code pass in development

Code review

• This pull request has a descriptive title and information useful to a reviewer. There may be a screenshot or screencast attached
• "Ready for review" label attached to the PR and reviewers assigned
• Issue from task tracker has a link to this pull request
• Changes have been reviewed by at least one other engineer

[cyrusradfar]

Thank you for documenting the changes so clearly