Make the rollout tests wait for the plan look to return before their cleanups restore what it reads, which raced (issue 1338)

cmd/mesh-controller/silent_mid_tier_integration_test.go

@@ -171,7 +171,9 @@ func TestAPlanPassesATierWhoseMachineNeverReportsAfterTheBoundAndSendsTheNextToT
 		}}
 	first, stopFirst := context.WithCancel(ctx)
 	defer stopFirst()
-	startRolloutEvents(first, open, js)
+	waitFirst := startRolloutEvents(first, open, js)
+	// Ends with the test before the cleanups restore what the look reads, which run after it (issue 1338).
+	t.Cleanup(func() { stopFirst(); waitFirst() })
 	if err := inv.SavePlan(ctx, &p); err != nil {
 		t.Fatal(err)
 	}