This is a reland of 4e1d7c87.
Failure on arm and arm64 is fixed by https://crrev.com/c/1411885.

Original change's description:
> [wasm] Split compilation in three stages
>
> In order to refactor ownership between objects in wasm compilation, the
> compilation (executed by background tasks) is split in three stages:
> getting a compilation unit (while holding a mutex), executing the work
> (without any mutex and without keeping the NativeModule alive), and
> submitting the work (with a mutex again).
>
> This CL prepares this design by splitting compilation from submission.
> Both steps are still executed right after each other. This will be
> changed in a follow-up CL.
>
> R=titzer@chromium.org
> CC=mstarzinger@chromium.org
>
> Bug: v8:8689
> Change-Id: I2f92aee8e2f2d45470d8c63314ed026341630902
> Reviewed-on: https://chromium-review.googlesource.com/c/1414920
> Reviewed-by: Ben Titzer <titzer@chromium.org>
> Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#58929}

TBR=titzer@chromium.org

Bug: v8:8689
Change-Id: I58ff07d0e0ac8df0f6ee23c416f992954f4673d2
Reviewed-on: https://chromium-review.googlesource.com/c/1422748Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58959}