Fix http://code.google.com/p/dart/issues/detail?id=15017.

tests/language/minify_closure_variable_collision_test.dart

+// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// Regression test for dart2js, that used to minify a captured
+// variable's name to the same name as inherited Object methods.
+
+var array = [new A()];
+
+class A {
+  operator==(other) {
+    return true;
+  }
+}
+
+foo() {
+  // Use lots of variables, to maximize the chance of collisions.
+  var a = 42;
+  var b = 42;
+  var c = 42;
+  var d = 42;
+  var e = 42;
+  var f = 42;
+  var g = 42;
+  var h = 42;
+  var i = 42;
+  var j = 42;
+  var k = 42;
+  var l = 42;
+  var m = 42;
+  var n = 42;
+  array[0] = () {
+    return a + b + c + d + e + f + g + h + i + j + k + l + m + n;
+  };
+}
+
+main() {
+  foo();
+  if (array[0] == new A()) {
+    throw 'Test failed';
+  }
+  if (array[0]() != 42 * 14) {
+    throw 'Test failed';
+  }
+}