Revert of [wasm] instantiate expressed in terms of compile (patchset #6 id:140001 of https://codereview.chromium.org/2806073002/ )

Reason for revert:
Roll blocker: https://bugs.chromium.org/p/chromium/issues/detail?id=710824

Original issue's description:
> [wasm] instantiate expressed in terms of compile
>
> Today, the semantics of:
>
> WebAssembly.instantiate
>
> and
>
> WebAssembly.compile().then(new WebAssemblyInstance)
>
> are subtly different, to the point where attempting the proposed
> change uncovered bugs.
>
> In the future, it's possible that .instantiate actually have different
> semantics - if we pre-specialized to the provided ffi, for example.
> Right now that's not the case.
>
> This CL:
> - gets our implementation closer to what developers may write using
> the compile -> new Instance alternative, in particular wrt promise
> creation. By reusing code paths, we uncover more bugs, and keep
> maintenance cost lower.
>
> - it gives us the response-based WebAssembly.instantiate implicitly.
> Otherwise, we'd need that same implementation on the blink side. The
> negative is maintenance: imagine if the bugs I mentioned could only be
> found when running in Blink.
>
> BUG=chromium:697028
>
> Review-Url: https://codereview.chromium.org/2806073002
> Cr-Commit-Position: refs/heads/master@{#44592}
> Committed: https://chromium.googlesource.com/v8/v8/+/7829af3275ff4644a2d0a1270abe1a1e4415e9fb

TBR=bradnelson@chromium.org,ahaas@chromium.org,adamk@chromium.org,mtrofin@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:697028

Review-Url: https://codereview.chromium.org/2810203002
Cr-Commit-Position: refs/heads/master@{#44614}