Enable ArrayBufferExtensions by default. The
last CL (https://crrev.com/c/2078585) that tried to enable this was
reverted because of a TSAN failure. This was fixed in
https://crrev.com/c/2078586.

Bug: v8:10064
Change-Id: I2c3e0f2614323ea1521f2085b3c2bda5b69418ad
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2083012Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66521}