The method changes a global flag, depending upon which v8 attaches or
not the SharedArrayBuffer constructor to global objects. Chrome ended
up calling it when some contexts had already been created, leading to
inconsistencies. (Also) because of that, we decided to change the
mechanism for enabling cross-origin isolation (cf.
https://crrev.com/c/2880215). I believe it is better not to expose
this method.

Bug: chromium:923807
Change-Id: I269cb1c5406f999a395bbb7657574c0f73b4ae99
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2900224Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Antonio Sartori <antoniosartori@chromium.org>
Cr-Commit-Position: refs/heads/master@{#74600}