integration: start informer and scheduler outside of InitTestScheduler

In case two or more controllers share the informers created through InitTestScheduler,
it's not safe to start the informers until all controllers set their informer
indexers. Otherwise, some controller might fail to register their indexers
in time. Thus, it's responsibility of each consumer to make sure all informers
are started after all controllers had time to get initiliazed.

test/integration/node/lifecycle_test.go

@@ -161,13 +161,14 @@ func TestTaintBasedEvictions(t *testing.T) {
 				return
 			}
 
-			go nc.Run(testCtx.Ctx.Done())
-
-			// Waiting for all controller sync.
+			// Waiting for all controllers to sync
 			externalInformers.Start(testCtx.Ctx.Done())
 			externalInformers.WaitForCacheSync(testCtx.Ctx.Done())
-			testCtx.InformerFactory.Start(testCtx.Ctx.Done())
-			testCtx.InformerFactory.WaitForCacheSync(testCtx.Ctx.Done())
+			testutils.SyncInformerFactory(testCtx)
+
+			// Run all controllers
+			go nc.Run(testCtx.Ctx.Done())
+			go testCtx.Scheduler.Run(testCtx.Ctx)
 
 			nodeRes := v1.ResourceList{
 				v1.ResourceCPU:    resource.MustParse("4000m"),