Chore: don't check Program.start in SourceCode#getComments (refs #14744)

[mdjermanovic]

Prerequisites checklist

• I have read the contributing guidelines.

What is the purpose of this pull request? (put an "X" next to an item)

[ ] Documentation update
[ ] Bug fix (template)
[ ] New rule (template)
[ ] Changes an existing rule (template)
[ ] Add autofixing to a rule
[ ] Add a CLI option
[ ] Add something to the core
[x] Other, please explain:

refs #14744

Refactors SourceCode#getComments() to retain the intended behavior when used with Espree 8 which sets Program.start and Program.end differently than Espree 7.

What changes did you make? (Give an overview)

Skip comparing comment's start/end with Program node's start/end, and thus don't break the loop that should get all comments around a top-level statement.

Program.start used to be 0 in Espree 7, so the condition was always false. Similar for Program.end, which used to be the last index.

I tried this with Espree 8.0.0-beta.1, all tests are passing except those for naming convention rules that will be fixed in #14591.

Is there anything you'd like reviewers to focus on?

[btmills]

I agree with not removing getComments() until v9 because of the timing with the upcoming v8 release. This logic change to fix it until then makes sense. Thanks for doing it!