[obj2yaml] - MIPS: move and improve testing of the e_flags
Mips/elf-flags.yaml and Mips/elf-abi.yaml are tests that intention was to
show that yaml2obj/obj2yaml are able to read/dump MIPS specific e_flags.
They were not complete, contained an excessive YAML parts and were placed
at a wrong location.
I removed them and created the obj2yaml/elf-mips-eflags.yaml instead.
Differential revision: https://reviews.llvm.org/D65807
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@368140 91177308-0d34-0410-b5e6-96231b3b80d8