Revert "Support dynamic as type literal."

sdk/lib/_internal/compiler/implementation/dart_backend/placeholder_collector.dart

Index: sdk/lib/_internal/compiler/implementation/dart_backend/placeholder_collector.dart
diff --git a/sdk/lib/_internal/compiler/implementation/dart_backend/placeholder_collector.dart b/sdk/lib/_internal/compiler/implementation/dart_backend/placeholder_collector.dart
index eb211bbc7645fc85560858b71eb3e36d05fdb944..c97e070f6e1c36c56da0f223b2f1f03eefdab187 100644
--- a/sdk/lib/_internal/compiler/implementation/dart_backend/placeholder_collector.dart
+++ b/sdk/lib/_internal/compiler/implementation/dart_backend/placeholder_collector.dart
@@ -314,7 +314,9 @@ class PlaceholderCollector extends Visitor {
       return;
     }
     if (element == compiler.dynamicClass) {
-      return;
+      internalError(
+          'Should never make element placeholder for dynamic type element',
+          node: node);
     }
     elementNodes.putIfAbsent(element, () => new Set<Node>()).add(node);
   }