vk/query: Don't emit a CS stall by itself

Both the bspec and the simulator don't like this.  I'm not sure if stalling
at the scoreboard is right but it at least shuts up the simulator.

src/vulkan/device.c

@@ -3317,7 +3317,8 @@ void anv_CmdCopyQueryPoolResults(
    /* FIXME: If we're not waiting, should we just do this on the CPU? */
    if (flags & VK_QUERY_RESULT_WAIT_BIT)
       anv_batch_emit(&cmd_buffer->batch, GEN8_PIPE_CONTROL,
-                     .CommandStreamerStallEnable = true);
+                     .CommandStreamerStallEnable = true,
+                     .StallAtPixelScoreboard = true);
 
    dst_offset = buffer->offset + destOffset;
    for (uint32_t i = 0; i < queryCount; i++) {