tcpip_test: add missing checkLayers()
tcpip_test: add missing checkLayers()

xuzhaokui/gopacket,rouzier/gopacket,levigross/gopacket,adriantam/gopacket,urso/gopacket,xuzhaokui/gopacket,vtolstov/gopacket,levigross/gopacket,breml/gopacket,ross-williams/gopacket,UIKit0/gopacket-1,UIKit0/gopacket-1,skyportsystems/gopacket,LrsK/gopacket,levigross/gopacket,nhooyr/gopacket,vtolstov/gopacket,google/gopacket,rouzier/gopacket,adriantam/gopacket,vtolstov/gopacket,ccordes-snaproute/gopacket,breml/gopacket,josephcopenhaver/gopacket,josephcopenhaver/gopacket,skyportsystems/gopacket,urso/gopacket,breml/gopacket,LrsK/gopacket,skyportsystems/gopacket,UIKit0/gopacket-1,nhooyr/gopacket,xuzhaokui/gopacket,LrsK/gopacket,ccordes-snaproute/gopacket,adriantam/gopacket,google/gopacket,josephcopenhaver/gopacket,google/gopacket,nhooyr/gopacket,ross-williams/gopacket,urso/gopacket,ccordes-snaproute/gopacket,ross-williams/gopacket,rouzier/gopacket