[llvm-objdump]Improve testing of some switches #1

This is the first in a set of patches I have to improve testing of
llvm-objdump. This patch targets --all-headers, --section, and
--full-contents. In the --section case, it deletes a pre-canned binary
which is only used by the one test and replaces it with yaml.

Reviewed by: grimar, MaskRay

Differential Revision: https://reviews.llvm.org/D61941

llvm-svn: 360893