Instead, make the array-allocating builtin initialize the object.
This speeds up later stages of Turbofan graph processing, in particular
live range computation.

Bug: v8:7748
Change-Id: Iba0d682922b444b1d6151eeaee8d939821ebc980
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2983457
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Maya Lekova <mslekova@chromium.org>
Reviewed-by: Manos Koukoutos <manoskouk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75367}