[Support] Remove getPathFromOpenFD, it was unused

Summary:
It was added to support clang warnings about includes with case
mismatches, but it ended up not being necessary.

Reviewers: twoh, rafael

Subscribers: hiraditya, llvm-commits

Differential Revision: https://reviews.llvm.org/D36328

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@310078 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed