[llvm] [lit] Fix tests when run via symlinks (PR #192530)

[Keith Smiley via llvm-commits]

keith wrote:

yea exactly, bazel's sandbox symlinks everything in to a separate directory to avoid the test seeing more files than it should. we could disable this for these tests on the bazel side to avoid this issue but this seemed reasonable enough to me

https://github.com/llvm/llvm-project/pull/192530