This is a further step to separate the implementation of the JavaScript
API from the internals of the WASM implementation. Now, wasm-js.cc
only needs to interact with the WASM engine and is (almost) independent
of module-decoder.h and module-compiler.h.

Also, move SyncCompileAndInstantiate() into wasm-module-runner.cc.

Bug: v8:7316

R=clemensh@chromium.org, mstarzinger@chromium.org

Cq-Include-Trybots: master.tryserver.chromium.linux:linux_chromium_rel_ng
Change-Id: I7765af54ac16f53a5ff88c17a22c5d36bacaf926
Reviewed-on: https://chromium-review.googlesource.com/870871
Commit-Queue: Ben Titzer <titzer@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50679}