Revert of [d8] Fix the shared-library build (patchset #12 id:20002 of https://codereview.chromium.org/2342563002/ )

Reason for revert:
Unblocking roll

Original issue's description:
> [d8] Fix the shared-library build
>
> This commit ensures that the d8 shared library build uses the same logic as
> the standard static build by exporting relevant functions and classes.
>
> BUG=chromium:646337
>
> Committed: https://crrev.com/2c10ca8086a4d595ecf9aa843d2031b068470d65
> Cr-Commit-Position: refs/heads/master@{#39503}

TBR=jochen@chromium.org,vogelheim@chromium.org,bmeurer@chromium.org,titzer@chromium.org,jgruber@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:646337

Review-Url: https://codereview.chromium.org/2356703003
Cr-Commit-Position: refs/heads/master@{#39526}