Make static tear-off closures a class, like instance tear-off closures.

tests/compiler/dart2js/pretty_parameter_test.dart

 // Copyright (c) 2011, 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.
 // Test that parameters keep their names in the output.
 
 import "package:expect/expect.dart";
 import 'compiler_helper.dart';
 
 const String FOO = r"""
 void foo(var a, var b) {
 }
 """;
 
 const String BAR = r"""
 void bar(var eval, var $eval) {
 }
 """;
 
 const String PARAMETER_AND_TEMP = r"""
 void bar(var t0, var b) {
   {
     var t0 = 2;
     if (b) {
+      bar(1, 2);
       t0 = 4;
     } else {
       t0 = 3;
     }
     print(t0);
   }
   print(t0);
 }
 """;
 
@@ skipping 21 matching lines @@
     print(a);
   }
   print(a);
 }
 """;
 
 const String PARAMETER_INIT = r"""
 int foo(var start, bool test) {
   var result = start;
   if (test) {
+    foo(1, 2);
     result = 42;
   }
   print(result);
 }
 """;
 
 main() {
   String generated = compile(FOO, entry: 'foo');
   Expect.isTrue(generated.contains(r"function(a, b) {"));
 
   generated = compile(BAR, entry: 'bar');
   Expect.isTrue(generated.contains(r"function($eval, $$eval) {"));
 
   generated = compile(PARAMETER_AND_TEMP, entry: 'bar');
   Expect.isTrue(generated.contains(r"print(t00)"));
   // Check that the second 't0' got another name.
   Expect.isTrue(generated.contains(r"print(t01)"));
 
   generated = compile(MULTIPLE_PHIS_ONE_LOCAL, entry: 'foo');
   Expect.isTrue(generated.contains("var a;"));
   // Check that there is only one var declaration.
   checkNumberOfMatches(new RegExp("var").allMatches(generated).iterator, 1);
 
   generated = compile(NO_LOCAL, entry: 'foo');
   Expect.isFalse(generated.contains('var'));
 
   generated = compile(PARAMETER_INIT, entry: 'foo');
-  Expect.isTrue(generated.contains('var result = test === true ? 42 : start'));
   // Check that there is only one var declaration.
   checkNumberOfMatches(new RegExp("var").allMatches(generated).iterator, 1);
 }