Implement supporting the array of array of image
type in uniform. Add a new end2end test for it.

Bug: angleproject:3881
Change-Id: Idd757ae1d0ed34d585ae1ca5e0b6577459a0acb7
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2379335
Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>