Simd float concrete comparisons (#81892)
There's no reason for these to ever be calls, so they should be
transparent instead of just aEIC. Also adds concrete versions of
comparisons with scalars, and filecheck tests to make sure these
generate 1-2 instruction sequences in release on arm64 (x86_64 is a
little trickier to test due to frame pointers, but if we get the right
codgen on arm64, in practice we do well on x86_64 for these too).
Also makes filecheck patterns for repeating initializers a bit more
robust.
