Revert of [compiler] Enable shared function marking by default (patchset #1 id:1 of https://codereview.chromium.org/2491773006/ )

Reason for revert:
Revert because it depends on https://codereview.chromium.org/2478323002/ which has been reverted.

Original issue's description:
> [compiler] Enable shared function marking by default
>
> BUG=v8:5512

TBR=bmeurer@chromium.org,leszeks@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:5512

Review-Url: https://codereview.chromium.org/2491643006
Cr-Commit-Position: refs/heads/master@{#40926}