[x86] Expose more of the condition conversion routines in the public API
for X86's instruction information. I've now got a second patch under
review that needs these same APIs. This bit is nicely orthogonal and
obvious, so landing it. NFC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@328944 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed