e2e framework: move node helper code into sub package

This reduces the size of the test/e2e/framework itself. Because it does not
check nodes anymore by default, E2E test suites must set their own check
function or set the original one by importing
"k8s.io/kubernetes/test/e2e/framework/todo/node/init".

test/e2e/framework/framework.go

@@ -471,13 +471,6 @@ func (f *Framework) AfterEach() {
 	}
 
 	printSummaries(f.TestSummaries, f.BaseName)
-
-	// Check whether all nodes are ready after the test.
-	// This is explicitly done at the very end of the test, to avoid
-	// e.g. not removing namespace in case of this failure.
-	if err := AllNodesReady(f.ClientSet, 3*time.Minute); err != nil {
-		Failf("All nodes should be ready after test, %v", err)
-	}
 }
 
 // DeleteNamespace can be used to delete a namespace. Additionally it can be used to