Go routine leaks in consul agent on 1.8.0

#### Overview of the Issue

I see large amount of go-routines even after all the services are de-registered with consul. These goroutines stay about the same even after a long time of idle time. This is with consul 1.8.0

### Consul info for both Client and Server
```
agent:
check_monitors = 0
check_ttls = 0
checks = 0
services = 0
build:
prerelease =
revision = 3111cb8c
version = 1.8.0
consul:
acl = disabled
known_servers = 1
server = false
runtime:
arch = amd64
cpu_count = 16
goroutines = 9491
max_procs = 16
os = linux
version = go1.14.4
serf_lan:
coordinate_resets = 0
encrypted = false
event_queue = 0
event_time = 2
failed = 0
health_score = 0
intent_queue = 0
left = 0
member_time = 3
members = 2
query_queue = 0
query_time = 1

```