Add a test for r221870

bad-relocs.obj.coff-i386 has a relocation whose symbol index is outside
the symbol table.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222413 91177308-0d34-0410-b5e6-96231b3b80d8
[ELF] Prevent ARM ELF object writer from generating deprecated relocation code R_ARM_PLT32

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222414 91177308-0d34-0410-b5e6-96231b3b80d8