[llvm-objcopy]Add coverage for --split-dwo and --output-format

Also fix up a couple of minor issues in the test being updated, where
FileCheck could match on incorrect output and fix the test case order to
match the struct order.

Reviewed by: grimar

Differential Revision: https://reviews.llvm.org/D59691


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@356746 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed