Fix lazy parsing for functions that use super.

test/mjsunit/harmony/classes-lazy-parsing.js

+// Copyright 2014 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --harmony-classes --min-preparse-length=0
+
+'use strict';
+
+class Base {
+  m() {
+    return 42;
+  }
+}
+
+class Derived extends Base {
+  m() {
+    return super.m();
+  }
+}
+
+assertEquals(42, new Derived().m());