Add test for failing assignment to super setter.

test/fixtures/esnext/es6-classes/getter-setter-super.js

@@ -2,6 +2,14 @@ class Base {
   get sound() {
     return 'I am a ' + this.type + '.';
   }
+
+  get name() {
+    return this._name;
+  }
+
+  set name(val) {
+    this._name = val;
+  }
 }
 
 class Animal extends Base {}
@@ -12,6 +20,15 @@ class Cat extends Animal {
   get sound() {
     return super.sound + ' MEOW!';
   }
+
+  set name(val) {
+    super.name = val;
+    this._name += ' Cat';
+  }
 }
 
-assert.equal(new Cat().sound, 'I am a cat. MEOW!');
+var cat = new Cat();
+
+assert.equal(cat.sound, 'I am a cat. MEOW!');
+cat.name = 'Nyan';
+assert.equal(new Cat().name, 'Nyan Cat');