Allow connecting to 9090 port in gke test clusters
Allow connecting to 9090 port in gke test clusters

The 9090 port is the default prometheus port which is used by some of
our testing tools, e.g. ClusterLoader2.
What we realized recently is that it's impossible to connect to
prometheus in private GKE clusters and changing the e2eAllow here fix
that.

dims/test-infra,dims/test-infra,kubernetes/test-infra,kubernetes/test-infra,fejta/test-infra,cjwagner/test-infra,michelle192837/test-infra,cblecker/test-infra,monopole/test-infra,brahmaroutu/test-infra,BenTheElder/test-infra,michelle192837/test-infra,cjwagner/test-infra,kubernetes/test-infra,brahmaroutu/test-infra,ixdy/kubernetes-test-infra,jessfraz/test-infra,michelle192837/test-infra,BenTheElder/test-infra,michelle192837/test-infra,cjwagner/test-infra,dims/test-infra,dims/test-infra,ixdy/kubernetes-test-infra,pwittrock/test-infra,monopole/test-infra,michelle192837/test-infra,jessfraz/test-infra,fejta/test-infra,jessfraz/test-infra,dims/test-infra,cjwagner/test-infra,jessfraz/test-infra,ixdy/kubernetes-test-infra,BenTheElder/test-infra,cblecker/test-infra,brahmaroutu/test-infra,monopole/test-infra,pwittrock/test-infra,monopole/test-infra,cblecker/test-infra,cblecker/test-infra,brahmaroutu/test-infra,kubernetes/test-infra,kubernetes/test-infra,brahmaroutu/test-infra,BenTheElder/test-infra,cblecker/test-infra,pwittrock/test-infra,jessfraz/test-infra,BenTheElder/test-infra,pwittrock/test-infra,monopole/test-infra,kubernetes/test-infra,pwittrock/test-infra,brahmaroutu/test-infra,fejta/test-infra,michelle192837/test-infra,cjwagner/test-infra,cblecker/test-infra,ixdy/kubernetes-test-infra,fejta/test-infra,jessfraz/test-infra,fejta/test-infra,monopole/test-infra,cjwagner/test-infra,BenTheElder/test-infra,dims/test-infra,ixdy/kubernetes-test-infra,fejta/test-infra