ofproto: add testcase for packet_in_mask bits in OFPT_SET_ASYNC configuration

Signed-off-by: Shu Shen <shu.shen@radisys.com>
ofproto: checking of packet_in_mask in async config

The check shall use wire protool reasons, which could be different from
the internal packet-in reason.

Signed-off-by: Shu Shen <shu.shen@radisys.com>