A previous CL lowered NumberConstant nodes into IntPtrConstant nodes during
simplified lowering. It inadvertently disabled an optimization in TypeArray
accesses that relied on matching NumberConstant(0).

Bug: chromium:806727
Change-Id: If1938af057be66dea8edc588cc048a01410ca0ad
Reviewed-on: https://chromium-review.googlesource.com/897494Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Pierre Langlois <pierre.langlois@arm.com>
Cr-Commit-Position: refs/heads/master@{#51092}