[Improvement] InstanceSet should be recoverable from a bad Template by Update the Template to a good one

[free6om]

Is your improvement request related to a problem? Please describe.

1. revision 1, 3 replicas with a bad Template that can't be scheduled properly (by unsatisfiable anti-affinity etc.)
2. 2 Pods in Pending phase and 1 Running
3. revision 2, update the Template to a good one that can be scheduled properly
4. Pods are still stuck in Pending phase

Describe the solution you'd like
Pods should become Running eventually with Template revision 2.