[MergeFunc] Update clang test for r350939

In r350939, the MergeFunc pass learned to erase duplicate functions
which are discardable if unused.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@350952 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed