Add port forwarding unit & integration tests

[priyawadhwa]

Add integration tests for #2593 to cover:

1. (Done with Add port forwarding integration test #2623) deleting a pod after port forwarding has occurred
2. changing the skaffold config after a dev loop
3. (Done with Monitor kubectl logs when port forwarding and retry on error #2543)making sure port forwarding works on the second dev loop

(Done with - #2648) Also, add constructor for portForwardEntry

Add unit tests for:

1. (Done with Add unit tests to kubectl forwarder #2661) kubectl forwarder
2. (Done with Add unit test for LoadOrStore  #2649) loadorstore