X86FixupBWInsts: Minor cleanup. NFC

Summary: Cleanup some remnants of code from when the X86FixupBWInsts pass did both forward liveness analysis and backward liveness analysis.

Reviewers: MatzeB, myatsina, DavidKreitzer

Reviewed By: MatzeB

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D31264

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@298599 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed