Autoscale Load Balancing Rule looses VMs during a node failure.

##### ISSUE TYPE

* Bug Report

##### COMPONENT NAME

~~~
Autoscaling, Load Balancer
~~~

##### CLOUDSTACK VERSION

~~~
4.19.0
~~~

##### CONFIGURATION

##### OS / ENVIRONMENT

##### SUMMARY

We have a few Autoscale Rules running in production. For simplicity, lets say we have 1 Autoscale Rule, with 4 VMs currently under the Rule.

2 of the VMs are located in a server that has experienced a node failure.

During the node failure, the VMs are restarted in a new node. The 2 VMs started up again in the new server. When you go to the Autoscale Load Balancing Rule, you will notice that these 2 VMs are not under the Autoscale Rule anymore. They are now orphans.

But, the autoscale rule will still state it has a total of 4 scaled up VMs

In summary,
- Total No. Of VMs resulting from Autoscale : 4 VMs
- No. of VMs under LB Rule: 2 VMs
- No. Of VMs as Orphans : 2VMs

##### STEPS TO REPRODUCE

~~~
- Create Autoscale Rule with Multiple VMs
- Live Migrate VMs to another host
- Force Power Off the Host to simulate node failure
- Wait for VMs to restart in new Node
- Go to Autoscale Load Balancer, and display the list of VMs under the load balancing rule
- If cannot replicate the issue, retry it again until it happens. It may be intermittent.
~~~

##### EXPECTED RESULTS

~~~
A logic should be implemented to:
- Scale up the VMs when it has detected the node is down (to fufill the scale up requirement)
- Do not restart the VMs from the host failure to prevent confusion.
~~~

##### ACTUAL RESULTS

~~~
VMs are missing from the load balancing rule
~~~