Texture2DArray binding function

Texture2DArray textures can now be bound properly.

Change-Id: I3516b67c266feaede3e63c30615bd9f2891c0f1b
Reviewed-on: https://swiftshader-review.googlesource.com/3083
Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>