Automatic merge from submit-queue

add delete-namespace-on-failure flag

I have been doing this for a while. 

Setting `--delete-namespace=false --clean-start=true` only works if you have only one e2e test running in a loop. 

This PR lets someone to set `delete-namespace-on-failure=false` and run multiple tests in parallel and preserve the crime scene. It makes it easier to reproduce failures. 

Let me know if this is worth it or there are some other tricks I am not aware.