[AMDGPU] Refactor and extend elf-header-flags-mach tests

* Factor out common elements of the input YAML document and use sed to
  macro replace the run line specific elements.
* Add checks for the common elements which depend on the ELF class.
* Use non-numeric suffix for temporary files to avoid merge conflicts.
* Sort tests by GFX# ascending.
* Group ELF and YAML tests by GFX#.

Reviewed By: t-tye

Differential Revision: https://reviews.llvm.org/D90245