Fix dumping logs for GCE scale tests

[upodroid]

Splitting #16181 to separate PRs

1. When a bastion is being used, kops tries to use it by its hostname which doesn't work with --dns=none. Using the IP address is much easier
2. we also dump the bastion IP in the logs
3. --max-nodes flag is now respected by the DumpAllNodes function.
4. kubetest2 now sets the --ssh-private-key automatically when running kops gce clusters, this flag must be set for the kops toolbox dump cmd to work
5. We calculate the correct internal IP addresses of GCE instances to use with bastions.

[upodroid]

/cc @hakman

[hakman]

@upodroid Please explain in the description what issue you are trying to fix here and how.

[upodroid]

Please explain in the description what issue you are trying to fix here and how.

Done

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: hakman

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[upodroid]

/retest