[test] support full log (#4071)
[test] support full log (#4071)

This is useful when more logs are enabled and the logs contain
"leader", "child", "router" or "leader".
bukepo/openthread,librasungirl/openthread,srickardti/openthread,lanyuwen/openthread,chshu/openthread,lanyuwen/openthread,librasungirl/openthread,chshu/openthread,bukepo/openthread,jwhui/openthread,openthread/openthread,abtink/openthread,abtink/openthread,srickardti/openthread,openthread/openthread,lanyuwen/openthread,librasungirl/openthread,srickardti/openthread,jwhui/openthread,abtink/openthread,lanyuwen/openthread,turon/openthread,lanyuwen/openthread,chshu/openthread,bukepo/openthread,openthread/openthread,jwhui/openthread,srickardti/openthread,bukepo/openthread,lanyuwen/openthread,chshu/openthread,turon/openthread,chshu/openthread,turon/openthread,openthread/openthread,abtink/openthread,turon/openthread,jwhui/openthread,chshu/openthread,librasungirl/openthread