Merge pull request #4699 from boyu0/iss3509_physics_switch_foreground_bug

closed #3509: Sprites with PhysicsBody moves to wrong position when swit...

cocos/2d/CCDirector.cpp

@@ -847,13 +847,10 @@ void Director::resume()
 
     setAnimationInterval(_oldAnimationInterval);
 
-    if (gettimeofday(_lastUpdate, nullptr) != 0)
-    {
-        CCLOG("cocos2d: Director: Error in gettimeofday");
-    }
-
     _paused = false;
     _deltaTime = 0;
+    // fix issue #3509, skip one fps to avoid incorrect time calculation.
+    setNextDeltaTimeZero(true);
 }
 
 // display the FPS using a LabelAtlas