The escape analysis is able to perform scalar replacement on JSArrays
with in-object properties (which currently only happens for subclasses
of the Array constructor), but the Deoptimizer didn't properly
materialized and initialized the values of the in-object fields so far.

Bug: chromium:772689, v8:6399
Change-Id: I6555a46773d2a1543db069142aa05f4337566b9c
Reviewed-on: https://chromium-review.googlesource.com/706781Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48365}