Prototype f32x4.trunc on ARM for both ARM v7 and ARM v8. ARM v8 has
support for vrintz, and for ARM v7 we fallback to runtime.

Since ARM v8 uses vrintz, which is the same instruction used for F32
trunc (scalar), wasm-compiler reuses the Float32RoundTruncate check.

Bug: v8:10553
Change-Id: I65ddc36ccff21f8f0ff21a6e768184c084ffcfea
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2256770
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Reviewed-by: Deepti Gandluri <gdeepti@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68498}