This avoids leaving the heap in an invalid state if a GC occurs during
population of the cloned property array, as is done in other IC
builtins.

BUG=chromium:904167, v8:7611
R=jkummerow@chromium.org, ishell@chromium.org

Change-Id: I0350ed2d65b72e299f7109b7d5aa86331f60e940
Reviewed-on: https://chromium-review.googlesource.com/c/1350282
Commit-Queue: Caitlin Potter <caitp@igalia.com>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57879}