[SimplifyCFG] use range-for-loops, tidy; NFCI

There seems to be something missing here as shown in PR34471:
https://bugs.llvm.org/show_bug.cgi?id=34471 


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@315855 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed