[macho2yaml] Refactor the DWARF section dumpers.

This patch refactors the DWARF section dumpers. When dumping a DWARF
section, if the DWARF parser fails to parse the section, we will dump it
as a raw content section. This patch also fixes a bug in
DWARFYAML::Data::isEmpty(). Finally, a test case that tests dumping the
__debug_aranges section is added.

Reviewed By: jhenderson, grimar

Differential Revision: https://reviews.llvm.org/D85506