In https://crrev.com/c/3131374 we switched some instructions to use
macro-assembler functions which can handle AVX and SSE. However for
Cvtsi2ss and Cvtsi2sd, the behavior subtly changed. The old behavior
directly called cvtsi2ss/cvtsi2sd in the code-generator. The new
behavior used the macro-assembler functions, which xor the dst operand.
This led to more instructions and larger code size in some benchmarks.
The xor is supposed to help reduce dependence chain length (see comments
on Cvtsi2ss), but doesn't seem to have helped in this benchmark.

So, partially revert the changes, and rename all affected IA32 opcodes
back to SSE.

Bug: chromium:1248509
Change-Id: Ie700e2980fe9ed083c1160bda3a28f64e1e43041
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3154349
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/main@{#76775}