Disables all optimizations for WeakMaps/WeakSets.

Bug: chromium:844008
Change-Id: I5395ce981bbdd0e8e03ba0821103afde0889cf56
Reviewed-on: https://chromium-review.googlesource.com/1102513
Commit-Queue: Dominik Inführ <dinfuehr@google.com>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53851}