Revert r374771 "[llvm-size] Tidy up error messages (PR42970)"

This reverts commit 83e52f5e.

Makes Object/macho-invalid.test fail everywhere, e.g. here:
http://lab.llvm.org:8011/builders/llvm-hexagon-elf/builds/23669/steps/test-llvm/logs/FAIL%3A%20LLVM%3A%3Amacho-invalid.test

llvm-svn: 374780