Add DartType.treatAsRaw to treat List<dynamic> as List in the backend.

sdk/lib/_internal/compiler/implementation/js_backend/runtime_types.dart

Index: sdk/lib/_internal/compiler/implementation/js_backend/runtime_types.dart
diff --git a/sdk/lib/_internal/compiler/implementation/js_backend/runtime_types.dart b/sdk/lib/_internal/compiler/implementation/js_backend/runtime_types.dart
index 6a52399aab731b6bd5be1ed0b455e82dbf9e07f4..fbb9da74b53d594c6b8a435f593e58c0ffca0ef9 100644
--- a/sdk/lib/_internal/compiler/implementation/js_backend/runtime_types.dart
+++ b/sdk/lib/_internal/compiler/implementation/js_backend/runtime_types.dart
@@ -162,7 +162,7 @@ class RuntimeTypes {
     compiler.resolverWorld.isChecks.forEach((DartType type) {
       if (type.kind == TypeKind.INTERFACE) {
         InterfaceType itf = type;
-        if (!itf.isRaw) {
+        if (!itf.treatAsRaw) {
           potentiallyAddForRti(itf.element);
         }
       } else {
@@ -559,7 +559,7 @@ class RuntimeTypes {
   static bool hasTypeArguments(DartType type) {
     if (type is InterfaceType) {
       InterfaceType interfaceType = type;
-      return !interfaceType.isRaw;
+      return !interfaceType.treatAsRaw;
     }
     return false;
   }
@@ -613,7 +613,7 @@ class TypeRepresentationGenerator extends DartTypeVisitor {
 
   visitInterfaceType(InterfaceType type, _) {
     jsAst.Expression name = getJavaScriptClassName(type.element);
-    return type.isRaw ? name : visitList(type.typeArguments, head: name);
+    return type.treatAsRaw ? name : visitList(type.typeArguments, head: name);
   }
 
   jsAst.Expression visitList(Link<DartType> types, {jsAst.Expression head}) {