This is a reland of edf90ee8

The fix here is to call GetUnusedRegister with {}, in
liftoff-assembler-ia32.h emit_i8x16_shri_u.

Original change's description:
> [wasm-simd][liftoff][ia32][x64] Implement i8x16 shr
>
> The code sequence is the same as TurboFan, only wrapped in a template to
> share the implementation.
>
> Bug: v8:9909
> Change-Id: I9c1b37bbfafe91d1bd8edd7f9dafd86ff1c07623
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2202723
> Commit-Queue: Zhi An Ng <zhin@chromium.org>
> Reviewed-by: Clemens Backes <clemensb@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#67842}

Bug: v8:9909
Change-Id: Id56a612cd6580c68a5129e71d7a0e7b29d64b368
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2204080Reviewed-by: Clemens Backes <clemensb@chromium.org>
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67873}