Peeling away layers of indirection. More to follow.

Change-Id: Ide15b9ece926f51d957de8fdc37829f02d86ca49
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1573700
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61035}

Imported from https://github.com/WebAssembly/wasm-c-api/ and
updated to work inside V8.
Tests will be added in an upcoming CL.

This is experimental; it is not yet recommended to rely on it.

Change-Id: I05914f4b63298bf7c848c4d4c8811f0f6eb882e3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1516478
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60910}