turnip: don't count for VK_DESCRIPTOR_TYPE_SAMPLER

Otherwise it might lead to VK_ERROR_OUT_OF_POOL_MEMORY when this type of descriptor is provided.

Fixes: c39afe68

Also fixes amber tests: ./tests/cases/address_modes_float.amber ./tests/cases/address_modes_int.amber ./tests/cases/magfilter_linear.amber ./tests/cases/magfilter_nearest.amber