Revert of [modules] Make duplicate export error deterministic. (patchset #2 id:20001 of https://codereview.chromium.org/2331003002/ )

Reason for revert:
Seems to break one of our arm64 bots: https://chromegw.corp.google.com/i/client.v8.ports/builders/V8%20Linux%20-%20arm64%20-%20sim%20-%20nosnap%20-%20debug/builds/2303

Original issue's description:
> [modules] Make duplicate export error deterministic.
>
> In case of duplicate exports, always report the error for the very last
> one.
>
> R=adamk@chromium.org
> BUG=v8:5358,v8:1569
>
> Committed: https://crrev.com/da1f911c4269048d24a3442791b18523455f3b24
> Cr-Commit-Position: refs/heads/master@{#39424}

TBR=adamk@chromium.org,neis@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:5358,v8:1569

Review-Url: https://codereview.chromium.org/2340903002
Cr-Commit-Position: refs/heads/master@{#39430}