[TD-6169]<fix>: windows dll client can not quit.

src/client/src/tscSystem.c

@@ -199,9 +199,7 @@ void taos_init_imp(void) {
 
   // In the APIs of other program language, taos_cleanup is not available yet.
   // So, to make sure taos_cleanup will be invoked to clean up the allocated resource to suppress the valgrind warning.
-#if !defined(TD_WINDOWS)
   atexit(taos_cleanup);
-#endif
 
   tscDebug("client is initialized successfully");
 }

src/util/src/tcache.c

@@ -537,7 +537,8 @@ void taosCacheCleanup(SCacheObj *pCacheObj) {
   pCacheObj->deleting = 1;
 
   // wait for the refresh thread quit before destroying the cache object.
-  while(atomic_load_8(&pCacheObj->deleting)) {
+  // But in the dll, the child thread will be killed before atexit takes effect.So here we only wait for one second.
+  for (int i = 0; i < 20&&atomic_load_8(&pCacheObj->deleting) != 0; i++) {
     taosMsleep(50);
   }