[llvm-readobj] [ARMWinEH] Print set_fp/add_fp differently in epilogues

This matches how e.g. stp/ldp and other opcodes are printed differently
for epilogues.

Also add a missing --strict-whitespace in an existing test that
was added explicitly for testing vertical alignment, and change to
using temp files for the generated object files.

Differential Revision: https://reviews.llvm.org/D87363