Note that this also makes it possible to move several classes
into the module-compiler.cc file and inline their implementations.

This also allows removing several uses of wasm-module.h from
other places in V8 that include wasm-objects.h.

R=yangguo@chromium.org,clemensh@chromium.org,ahaas@chromium.org

Bug: 
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_chromium_rel_ng
Change-Id: I303ee2bb49dc53c951d377a1b65699c1e0e91da7
Reviewed-on: https://chromium-review.googlesource.com/687494Reviewed-by: Yang Guo <yangguo@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Ben Titzer <titzer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48204}