Revert of [wasm] Refactor import handling for 0xC. (patchset #10 id:180001 of https://codereview.chromium.org/2390113003/ )

Reason for revert:
Failes a few GC stress tests.https://chromegw.corp.google.com/i/client.v8/builders/V8%20Linux%20-%20gc%20stress/builds/6253

Original issue's description:
> [wasm] Refactor import handling for 0xC.
>
> Imports and exports in 0xC can be much more than functions, including
> tables, memories, and globals. This CL refactors the underlying
> organization of imports and exports to support these new import types.
>
> BUG=
>
> Committed: https://crrev.com/599f8a83420346d9cba5ff97bd2a7520468207b6
> Cr-Commit-Position: refs/heads/master@{#40033}

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

Review-Url: https://codereview.chromium.org/2395133002
Cr-Commit-Position: refs/heads/master@{#40038}