[X86] Rename hasNoSignedComparisonUses to hasNoSignFlagUses. Add the...

[X86] Rename hasNoSignedComparisonUses to hasNoSignFlagUses. Add the instruction that only modify the O flag to the waiver list.

The only caller of this turns CMP with 0 into TEST. CMP with 0 and TEST both set OF to 0 so we should have no issues with instructions that only use OF.

Though I don't think there's any reason we would read just OF after a compare with 0 anyway. So this probably isn't an observable change.

llvm-svn: 349223