There is no ELF ABI version enum.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184267 91177308-0d34-0410-b5e6-96231b3b80d8
[yaml2obj][ELF] Support ELFOSABI_* enum.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184268 91177308-0d34-0410-b5e6-96231b3b80d8
[yaml2obj][ELF] Beef up this test a bit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184269 91177308-0d34-0410-b5e6-96231b3b80d8