remove glob experiment since glob support is released

[jakecoffman]

What are you trying to accomplish?

We put glob support behind a feature flag so it could be rolled out and tested.

The feature is now released, we can remove this code.

Anything you want to highlight for special attention from reviewers?

Nope, I just got rid of dependency_files_for_globs and pulled the implementation up into dependency_files_for_multi_directories so the diff looks complicated.

How will you know you've accomplished your goal?

Removing code that is no longer being run, so we shouldn't see any change.

Checklist

• I have run the complete test suite to ensure all tests and linters pass.
• I have thoroughly tested my code changes to ensure they work as expected, including adding additional tests for new functionality.
• I have written clear and descriptive commit messages.
• I have provided a detailed description of the changes in the pull request, including the problem it addresses, how it fixes the problem, and any relevant details about the implementation.
• I have ensured that the code is well-documented and easy to understand.