Add substitutions even when type arguments are fixed.

sdk/lib/_internal/compiler/implementation/js_emitter/type_test_emitter.dart

Index: sdk/lib/_internal/compiler/implementation/js_emitter/type_test_emitter.dart
diff --git a/sdk/lib/_internal/compiler/implementation/js_emitter/type_test_emitter.dart b/sdk/lib/_internal/compiler/implementation/js_emitter/type_test_emitter.dart
index 076240a311c115de4069d07fde1e22ac6293a403..bf66d9bd43f144ae4d01861d570ac0d82ab11ed2 100644
--- a/sdk/lib/_internal/compiler/implementation/js_emitter/type_test_emitter.dart
+++ b/sdk/lib/_internal/compiler/implementation/js_emitter/type_test_emitter.dart
@@ -123,7 +123,7 @@ class TypeTestEmitter extends CodeEmitterHelper {
 
     bool haveSameTypeVariables(ClassElement a, ClassElement b) {
       if (a.isClosure()) return true;
-      return a.typeVariables == b.typeVariables;
+      return backend.rti.isTrivialSubstitution(a, b);
     }
 
     if (superclass != null && superclass != compiler.objectClass &&
@@ -135,9 +135,12 @@ class TypeTestEmitter extends CodeEmitterHelper {
       Set<ClassElement> emitted = new Set<ClassElement>();
       // TODO(karlklose): move the computation of these checks to
       // RuntimeTypeInformation.
-      if (backend.classNeedsRti(cls)) {
-        emitSubstitution(superclass, emitNull: true);
-        emitted.add(superclass);
+      while (superclass != null) {
+        if (backend.classNeedsRti(superclass)) {
+          emitSubstitution(superclass, emitNull: true);
+          emitted.add(superclass);
+        }
+        superclass = superclass.superclass;
       }
       for (DartType supertype in cls.allSupertypes) {
         ClassElement superclass = supertype.element;