Revert of [heap] Separate out optimized code map processing. (patchset #3 id:40001 of https://codereview.chromium.org/1426953006/ )

Reason for revert:
Breaks build: https://uberchromegw.corp.google.com/i/client.v8/builders/V8%20Linux%20-%20nosnap%20-%20debug/builds/3565

Original issue's description:
> [heap] Separate out optimized code map processing.
>
> This separates the post-processing step for optimized code maps out of
> the CodeFlusher. It uses the complete SharedFunctionInfo::Iterator to
> visit all candidates instead of gathering candidates during marking.
>
> Gathering candidates during marking no longer makes sense, now that the
> majority of SharedFunctionInfo objects will hold such an optimized code
> map. Also it reduces complexity of the implementation. Also conflating
> this mechanism with "code flushing" was confusing.
>
> R=ulan@chromium.org
>
> Committed: https://crrev.com/8ad6168d197dd167235c9d342ec7ce37b0daa88b
> Cr-Commit-Position: refs/heads/master@{#31830}

TBR=ulan@chromium.org,yangguo@chromium.org,mvstanton@chromium.org,mstarzinger@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.chromium.org/1434503003

Cr-Commit-Position: refs/heads/master@{#31832}