OpenGL has separate implementation-defined texture size limits, for
3D textures and array textures. For now just give them the same value.

Bug chromium:835299

Change-Id: Ifaf537511f016e21992388f56598d5ec12a393b8
Reviewed-on: https://swiftshader-review.googlesource.com/18788Tested-by: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>