Whitespace.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182819 91177308-0d34-0410-b5e6-96231b3b80d8
LoopVectorize.cpp: Fix abuse of StringRef on Twine. Twine captures the pointer of StringRef.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182820 91177308-0d34-0410-b5e6-96231b3b80d8