SimdAsHWIntrinsic improvements and cleanup (#80134)

SimdAsHWIntrinsic improvements and cleanup (#80134)

* Merge common code paths in simdashwintrinsic.cpp

* Fixing a bug in the WithElement node for CreateFromVector

* Ensure simdashwintrinsic paths consistently use the gtNewSimd*Node helpers where one path was already

* Ensure remaining simdashwintrinsic paths use the gtNewSimd*Node helpers

* Consistently use fgMakeMultiUse in the gtNewSimd*Node APIs

* Applying formatting patch

* Ensure isSimdAsHWIntrinsic gets passed through

* Revert "Consistently use fgMakeMultiUse in the gtNewSimd*Node APIs"

This reverts commit edb2ce8aa64c123f9407bd2a2f44c08900c54295.

* Handle SN_op_UnaryNegation for Vector2/3/4 on Mono

* Ensure short, ushort, float, and double don't assert for Vector128_Dot on downlevel hardware