[test] Actually check the common parts in CodeGen/ARM/global-merge-external.ll. NFC.

Previously, these parts weren't ever checked. The label patterns
need to be extended to match successfully on macho.

Differential Revision: https://reviews.llvm.org/D42126

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@322900 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed