InstrProfTest.cpp: Don't assume string literals are always merged.

MSC18 Debug didn't merge them.

FIXME: I tweaked just to appease a builder. Almost string literals should be addressed identically there.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@256459 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed