fix: dont generate build files in symlinked node_modules

[soldair]

PR Checklist

Please check if your PR fulfills the following requirements:

• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature (please, look at the "Scope of the project" section in the README.md file)
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Documentation content changes
• Other... Please describe:

What is the current behavior?

when local packages already managed with build files are linked into node_modules they may be erroneously re-exported causing directory has a BUILD file failures.

this should be a fix for #871

What is the new behavior?

when searching for packages under a given path if one is a symlink it'll be skipped.

Does this PR introduce a breaking change?

• Yes
• No

Other information

[alexeagle]

note from in-person discussion: we tested this manually, and it solves our immediate problem.

we need better testing for this which we'll add as we port it to typescript

[alexeagle]

what happened with this one? I'm still getting all the BUILD.bazel files renamed in the project after testing in windows-mode