Merging r328944:

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r328944 | chandlerc | 2018-04-01 14:47:55 -0700 (Sun, 01 Apr 2018) | 4 lines

[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.
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llvm-svn: 332564