[clang] [clang][ExtractAPI] Ensure LocationFileChecker doesn't try to traverse VFS when determining file path (PR #74071)

[Daniel Grumberg via cfe-commits]

daniel-grumberg wrote:

Awesome! Let me know if you need any clarification as the semantic is now different from what it was originally and what it was after your patch.

https://github.com/llvm/llvm-project/pull/74071