Correct last delta time (cocos2d#18898)

AIGRIND-LLC · minggo · commit a6530a5aca3b · 2018-09-20T18:03:30.000+08:00
If next delta time was zeroed (via setNextDeltaTimeZero) the last update time was not corrected.
diff --git a/cocos/base/CCDirector.cpp b/cocos/base/CCDirector.cpp
@@ -376,6 +376,7 @@ void Director::calculateDeltaTime()
     {
         _deltaTime = 0;
         _nextDeltaTimeZero = false;
+        _lastUpdate = std::chrono::steady_clock::now();
     }
     else
     {

Original file line number	Diff line number	Diff line change
`@@ -376,6 +376,7 @@ void Director::calculateDeltaTime()`
`376`	`376`	`{`
`377`	`377`	`_deltaTime = 0;`
`378`	`378`	`_nextDeltaTimeZero = false;`
	`379`	`+ _lastUpdate = std::chrono::steady_clock::now();`
`379`	`380`	`}`
`380`	`381`	`else`
`381`	`382`	`{`