Rollup merge of #130752 - tdittr:cmse-assembly-tests, r=jieyouxu

Improve assembly test for CMSE ABIs

Tracking issues: #75835 #81391

This ensures the code-gen for these ABIs does not change silently. There is a small chance that this code-gen might change, however even GCC (https://godbolt.org/z/16arxab5x and https://godbolt.org/z/16arxab5x) generates almost the same assembly for these ABIs. I hope the notes in the comments should help fix the tests if it ever breaks.

Author: tgross35