[IfConversion] Hoist removeBranch calls out of if/else clauses [NFC]

Summary:
Also added a comment.

Pulled out of https://reviews.llvm.org/D34099.

Reviewers: iteratee

Reviewed By: iteratee

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D34388

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@306279 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed