Convert a use of sys::Path.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184412 91177308-0d34-0410-b5e6-96231b3b80d8
Use the simpler sys::fs::exists.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184413 91177308-0d34-0410-b5e6-96231b3b80d8
Remove unused methods.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184415 91177308-0d34-0410-b5e6-96231b3b80d8
Remove more unused functions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184416 91177308-0d34-0410-b5e6-96231b3b80d8