Remove function names on function expressions.

tests/compiler/dart2js_extra/closure_test.dart

 // Copyright (c) 2012, 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.
 
 import "package:expect/expect.dart";
 
 closure0() {
-  // TODO(floitsch): remove name from functions.
-  var f = fun() { return 499; };
+  var f = () { return 499; };
   Expect.equals(499, f());
 }
 
 class A {
   closure1() {
-    var f = fun() { return 499; };
+    var f = () { return 499; };
     Expect.equals(499, f());
   }
 }
 
 applyFun(f) {
   return f();
 }
 
 closure2() {
-  Expect.equals(499, applyFun(fun() { return 499; }));
+  Expect.equals(499, applyFun(() { return 499; }));
 }
 
 closure3() {
-  var f = fun(x) { return 400 + x; };
+  var f = (x) { return 400 + x; };
   Expect.equals(499, f(99));
 }
 
 applyFun2(f) {
   return f(400, 99);
 }
 
 closure4() {
-  Expect.equals(499, applyFun2(fun(x, y) { return x + y; }));
+  Expect.equals(499, applyFun2((x, y) { return x + y; }));
 }
 
 main() {
   closure0();
   new A().closure1();
   closure2();
   closure3();
   closure4();
 }