Something doesn't seem quite right here; I would have expected changes to the GL and Vulkan runners to pass the UAV counter bindings through vkd3d_shader_interface_info.uav_counters.
I think things end up more or less working out for this test because spirv_compiler_get_descriptor_binding() ends up in the automatic binding assignment path due to "uav_counter_count" being 0, but I don't think that's how we want to handle UAV counters in the shader runner.