Optimize eliminate FP mechanism. This time optimize a function which has
no call but fixed stack objects. LLVM eliminates FP on such functions now.
Also, optimize GOT/PLT registers save/restore instructions if a given
function doesn't uses them. In addition, remove generating mechanism of
`.cfi` instructions since those are taken from other architectures and not
inspected yet. Update regression tests, also.
Reviewed By: simoll
Differential Revision: https://reviews.llvm.org/D92251
Optimize emitSPAdjustment function to generate as small as possible
instructions to adjust SP.
Reviewed By: simoll
Differential Revision: https://reviews.llvm.org/D92174
Kazushi (Jam) Marukawa