fix directory matching with trailing slashes

[Trott]

What is the purpose of this pull request?

Addresses #290.

What changes did you make? (Give an overview)

I added the tests in #291, reverted the refactoring commit that caused the issue, sorted out merge conflicts during the revert, and modified the tests as appropriate. There are a small number of test cases in the smoke tests from #291 that still do not pass, but I think this is still worth landing and releasing. (FWIW, this issue is keeping me from updating to fast-glob@3 on at least one project.)

[Trott]

The linter was complaining about a missing plugin for me when I tried to run it locally. Guess it works fine on CI and I should look into what was going on there.... Anyway, I'll get these lint errors fixed...

[Trott]

The linter was complaining about a missing plugin for me when I tried to run it locally. Guess it works fine on CI and I should look into what was going on there.... Anyway, I'll get these lint errors fixed...

FWIW, npm install doesn't result in a working linter on GitPod, but it works fine locally. Using yarn instead on GitPod works. I don't know why that is. Probably some global npm config file somewhere.

[mrmlnc]

@Trott, thanks for investigating the problem and the detailed description. I made changes in #339 based on your changes with minor remarks to satisfy all tests from #291.