F32x4 and F64x2 pmin and pmax were accepted into the proposal [0], this
removes all the ifdefs and todo guarding the prototypes, and moves these
instructions out of the post-mvp flag.

[0] https://github.com/WebAssembly/simd/pull/122

Bug: v8:10904
Change-Id: I4e0c2f29ddc5d7fc19a209cd02b3d369617574a0
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2405802Reviewed-by: Bill Budge <bbudge@chromium.org>
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69855}