Avoiding the builtin call, and potentially enabling other Turbofan
optimizations to apply.
This required teaching the MemoryLowering pass how to produce
Wasm-style isolate-independent code, where external references won't
work, and builtin calls have to be encoded differently.

Bug: v8:7748
Change-Id: Ib6d87da644330e7c3623c11aa333b23074aeae19
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3038524
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Manos Koukoutos <manoskouk@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75824}