ac: remove arrays when when querying sampler info
Fixes the following ARB_arrays_of_arrays piglit tests:
basic-imagestore-const-uniform-index
basic-imagestore-mixed-const-non-const-uniform-index
basic-imagestore-mixed-const-non-const-uniform-index2
basic-imagestore-non-const-uniform-index
Reviewed-by:
Nicolai Hähnle <nicolai.haehnle@amd.com>