There is exactly one WasmEngine per process, hence we do not need to
store or pass a pointer to it. We just use {GetWasmEngine} (which just
reads a global variable) whenever we need it.

R=jkummerow@chromium.org

Bug: v8:11879
Change-Id: I7e0e86e326f4cafe5a894af0ff6d35803c0340a9
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2972725
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Maya Lekova <mslekova@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75266}