[ELF] - Simplify the conflict-variable-linkage-name.s test case. [NFC]

This is a follow up requested during post commit review for
"[lld] r333880 - [ELF] - Also use DW_AT_linkage_name when gathering information about variables for error messages."

It removes checking of the input objects since it is really excessive.

llvm-svn: 334946