Add a smoke test that checks for the existence of some representative
paths from the apiextensions-server and the kube-aggregator server,
both part of the delegation chain in kube-apiserver.
abstract out etcd server creation
test/integration/framework: cleanup master_utils.go
kube-apiserver: move StartTestServer tests into test/integration/master
Fix the failing scale test
kube-apiserver's TestServer now returns a struct instead of individual values
