[gold] Fix error report in thinlto_emit_linked_objects.ll test

Summary:
It's just cleanup after r323818 to avoid irrelevant error message inside the test.
Existing version of test passed but generated unrelated error report about
symbol redefinition.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@325080 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed