Don't load collection/table node just to wait for updates to be committed (facebookarchive#3182)

- Because there would be no update otherwise.

Author: nguyenhuy

Source/ASCollectionNode.mm

@@ -519,7 +519,10 @@ - (void)performBatchUpdates:(void (^)())updates completion:(void (^)(BOOL))compl
 
 - (void)waitUntilAllUpdatesAreCommitted
 {
-  [self.view waitUntilAllUpdatesAreCommitted];
+  ASDisplayNodeAssertMainThread();
+  if (self.nodeLoaded) {
+    [self.view waitUntilAllUpdatesAreCommitted];
+  }
 }
 
 - (void)reloadDataWithCompletion:(void (^)())completion

Source/ASTableNode.mm

@@ -653,7 +653,10 @@ - (void)moveRowAtIndexPath:(NSIndexPath *)indexPath toIndexPath:(NSIndexPath *)n
 
 - (void)waitUntilAllUpdatesAreCommitted
 {
-  [self.view waitUntilAllUpdatesAreCommitted];
+  ASDisplayNodeAssertMainThread();
+  if (self.nodeLoaded) {
+    [self.view waitUntilAllUpdatesAreCommitted];
+  }
 }
 
 #pragma mark - Debugging (Private)