[ELF] Check for target architecture.

The canParse function for all the ELF subtargets check if the input files match
the subtarget.

There were few mismatches in the input files that didnt match the subtarget for
which the link was being invoked, which also acts as a test for this change.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@220182 91177308-0d34-0410-b5e6-96231b3b80d8