[android] disable UART echo (#3421)
[android] disable UART echo (#3421)


erja-gp/openthread,lanyuwen/openthread,jwhui/openthread,jwhui/openthread,bukepo/openthread,bukepo/openthread,openthread/openthread,librasungirl/openthread,chshu/openthread,abtink/openthread,librasungirl/openthread,lanyuwen/openthread,lanyuwen/openthread,openthread/openthread,openthread/openthread,erja-gp/openthread,chshu/openthread,abtink/openthread,srickardti/openthread,srickardti/openthread,erja-gp/openthread,turon/openthread,chshu/openthread,srickardti/openthread,bukepo/openthread,turon/openthread,lanyuwen/openthread,abtink/openthread,chshu/openthread,erja-gp/openthread,abtink/openthread,erja-gp/openthread,srickardti/openthread,librasungirl/openthread,chshu/openthread,jwhui/openthread,lanyuwen/openthread,turon/openthread,librasungirl/openthread,bukepo/openthread,chshu/openthread,erja-gp/openthread,lanyuwen/openthread,openthread/openthread,turon/openthread,jwhui/openthread