Fix unstable test TestRegisterMonitor_heartbeat (#4568)
Fix unstable test TestRegisterMonitor_heartbeat (#4568)


kingland/consul,vamage/consul,kingland/consul,hashicorp/consul,hashicorp/consul,youhong316/consul,youhong316/consul,scalp42/consul,scalp42/consul,vamage/consul,youhong316/consul,scalp42/consul,scalp42/consul,vamage/consul,scalp42/consul,hashicorp/consul,kingland/consul,youhong316/consul,vamage/consul,vamage/consul,42wim/consul,youhong316/consul,42wim/consul,kingland/consul,kingland/consul,42wim/consul,hashicorp/consul,42wim/consul,42wim/consul