Instead of having fast path for proxy only in Reflect.deleteProperty, it
is also in delete operator.

Bug: v8:6664
Change-Id: I3db919953e31f51a5dc4a504062bd691a6e17446
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1717660
Commit-Queue: Z Nguyen-Huu <duongn@microsoft.com>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Maya Lekova <mslekova@chromium.org>
Reviewed-by: Simon Zünd <szuend@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63014}