SIMD has been pretty stable for a while now, we are not expecting big
changes (like opcode renumbers), there might be new instructions added,
and they will all be backwards-compatible.

The reference interpreter in the SIMD proposal is now capable of
generating JS files for all test cases, so we can now run them.

There is a bit of tweaking necessary, since SIMD tests are in
tests/core/simd subfolder in the spec, so we need to change the glob
into a find that will traverse into subdirectory.

Bug: v8:10835
Change-Id: I1f7e3cf37f21b2aa2537d1e34242da2373bbf626
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2378587
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69793}