Merging r329414:

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r329414 | ctopper | 2018-04-06 09:16:43 -0700 (Fri, 06 Apr 2018) | 3 lines

[X86] Merge itineraries for CLC, CMC, and STC.

These are very simple flag setting instructions that appear to only be a single uop. They're unlikely to need this separation.
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llvm-svn: 332565