We were only reading back a single location, rather than multiple
locations required for arrayed types.

Test: Angry Birds 2 MEC
Bug: b/157672184
Change-Id: I8029dc5ece3b9dbff7c3c84c188996e622362767
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2231804
Commit-Queue: Cody Northrop <cnorthrop@google.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>