Make them accessible through MCInstrInfo. They are only used for debugging purposes so this doesn't
have an impact on performance. X86MCTargetDesc.o goes from 630K to 461K on x86_64.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150245 91177308-0d34-0410-b5e6-96231b3b80d8