This reverts commit bf9ab729.

Reason for revert:
https://build.chromium.org/p/client.v8/builders/V8%20Win64%20-%20debug/builds/22169

Original change's description:
> [in-place weak refs] Use WeakArray in Script::shared_function_infos.
> 
> For serializer changes, see goo.gl/Kh2eop
> 
> BUG=v8:7308
> 
> Cq-Include-Trybots: luci.chromium.try:linux_chromium_rel_ng
> Change-Id: I2b790413a4c0d8c8cc0c07ba7b901c965d64eb11
> Reviewed-on: https://chromium-review.googlesource.com/955593
> Commit-Queue: Marja Hölttä <marja@chromium.org>
> Reviewed-by: Yang Guo <yangguo@chromium.org>
> Reviewed-by: Hannes Payer <hpayer@chromium.org>
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#51895}

TBR=ulan@chromium.org,marja@chromium.org,yangguo@chromium.org,hpayer@chromium.org

Change-Id: Ib9552d5c2c284ff27463e61a054c60cc20f2f8cc
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:7308
Cq-Include-Trybots: luci.chromium.try:linux_chromium_rel_ng
Reviewed-on: https://chromium-review.googlesource.com/960121Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51896}