Revert "Model 'await for' as an explicit node in tree and fix its handling."

pkg/compiler/lib/src/scanner/listener.dart

Index: pkg/compiler/lib/src/scanner/listener.dart
diff --git a/pkg/compiler/lib/src/scanner/listener.dart b/pkg/compiler/lib/src/scanner/listener.dart
index 568577a86c183b060d20921c58f35bfbf7fa7d4a..0ef1f5db15af6991c96040f33180819a647c0260 100644
--- a/pkg/compiler/lib/src/scanner/listener.dart
+++ b/pkg/compiler/lib/src/scanner/listener.dart
@@ -2161,13 +2161,8 @@ class NodeListener extends ElementListener {
     Statement body = popNode();
     Expression expression = popNode();
     Node declaredIdentifier = popNode();
-    if (awaitToken == null) {
-      pushNode(new SyncForIn(declaredIdentifier, expression, body,
-                             forToken, inKeyword));
-    } else {
-      pushNode(new AsyncForIn(declaredIdentifier, expression, body, awaitToken,
-                              forToken, inKeyword));
-    }
+    pushNode(new ForIn(declaredIdentifier, expression, body,
+                       awaitToken, forToken, inKeyword));
   }
 
   void endMetadataStar(int count, bool forParameter) {