As Blink needs a way to delete a property without running a script,
make Object::Delete use ENTER_V8_NO_SCRIPT if the receiver object is
not a JSProxy.  Also makes Object::DeletePrivate use
ENTER_V8_NO_SCRIPT, too.

Bug: chromium:728583
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_chromium_rel_ng
Change-Id: Ib37959764b99a68d730d1bbc6dba410106d4f452
Reviewed-on: https://chromium-review.googlesource.com/608348Reviewed-by: Adam Klein <adamk@chromium.org>
Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Commit-Queue: Yuki Shiino <yukishiino@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47779}