Use a copy for transferring non detachable buffers

Currently, |DOMArrayBuffer::Transfer()| makes a copy, but still uses
the original buffer for transferring, thus making it possible to share a
regular ArrayBuffer (not SAB) with multiple threads.

(cherry picked from commit 0d289da12075592372940a366ad565b9a13d57ce)

Bug: 1177341
Change-Id: Idb48deb1698fe555f32531bc04b55dd3e1fb0a06
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2690630
Reviewed-by: Bill Budge bbudge@chromium.org
Reviewed-by: Andreas Haas ahaas@chromium.org
Reviewed-by: Daniel Cheng dcheng@chromium.org
Commit-Queue: Sergei Glazunov glazunov@google.com
Commit-Queue: Daniel Cheng dcheng@chromium.org
Cr-Original-Commit-Position: refs/heads/master@{#853272}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2691251
Reviewed-by: Krishna Govind govind@chromium.org
Commit-Queue: Krishna Govind govind@chromium.org
Cr-Commit-Position: refs/branch-heads/4389@{#980}
Cr-Branched-From: 9251c5db2b6d5a59fe4eac7aafa5fed37c139bb7-refs/heads/master@{#843830}

Notes: Security: backported fix for 1177341.