[clang-tidy] RenamerClangTidy wont emit fixes in scratch space
Prevent fixes being displayed if usages are found in the scratch buffer.
See Fix-It hints are being generated in the ScratchBuffer.
It may be wise down the line to put in a general fix in clang-tidy to prevent ScratchBuffer replacements being applied, but for now this will help.
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D82162