header-checker: header-abi-dumper should use ModuleIR instead

This commit redirects header-abi-dumper output to ModuleIR and then
write ModuleIR with `IRDumper::Dump(module)`.  This decouples ABI
information extraction from IRDumper and allows post-processing ModuleIR
before writing to files.

This commit also sorts the reference test data.

Test: ./tests/test.py
Change-Id: Ibc7a9a94c08df496ff76351f951170bddc1a66a9
29 files changed