Null checks were not optimized out for non-nullable arrays for array.len.
This CL brings array.len in line with the rest of the gc operations.

Bug: v8:7748
Change-Id: I8d4d5f159ed220f6e64cb812079e15d6e92de68b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2567690Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71529}