[clang] [CIR][AArch64] Handle constrained Neon FMA and sqrt (PR #218307)

[Yair Ben Avraham via cfe-commits]

yairbenavraham wrote:

> @yairbenavraham , please remove the original tests so that there are no duplicates. Thank you!

@banach-space , Addressed: the focused neon/*-constrained.c files now run the matching classic Clang checks as well as CIR checks. I removed the 15 superseded constrained test blocks from the legacy files. Tests of the same intrinsics in non-constrained files remain intentionally - they cover the default FP mode, not duplicate strict-FP coverage.

https://github.com/llvm/llvm-project/pull/218307