dart2js: Move most of the code_emitter_task code into the program-builder.

tests/compiler/dart2js/deferred_load_graph_segmentation_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.
 
 // Test of the graph segmentation algorithm used by deferred loading
 // to determine which elements can be deferred and which libraries
 // much be included in the initial download (loaded eagerly).
 
 import 'package:expect/expect.dart';
 import "package:async_helper/async_helper.dart";
@@ skipping 43 matching lines @@
     var inputElement = classes.where((e) => e.name == 'InputElement').single;
     var lib1 = lookupLibrary("memory:lib1.dart");
     var foo1 = lib1.find("foo1");
     var lib2 = lookupLibrary("memory:lib2.dart");
     var foo2 = lib2.find("foo2");
     var lib3 = lookupLibrary("memory:lib3.dart");
     var foo3 = lib3.find("foo3");
     var lib4 = lookupLibrary("memory:lib4.dart");
     var bar1 = lib4.find("bar1");
     var bar2 = lib4.find("bar2");
-    var outputClassLists = backend.emitter.outputClassLists;
 
     OutputUnit ou_lib1 = outputUnitForElement(foo1);
     OutputUnit ou_lib2 = outputUnitForElement(foo2);
     OutputUnit ou_lib1_lib2 = outputUnitForElement(foo3);
     OutputUnit ou_lib4_1 = outputUnitForElement(bar1);
     OutputUnit ou_lib4_2 = outputUnitForElement(bar2);
 
     Expect.equals(mainOutputUnit, outputUnitForElement(main));
     Expect.notEquals(mainOutputUnit, outputUnitForElement(foo1));
     Expect.notEquals(ou_lib1, ou_lib1_lib2);
@@ skipping 88 matching lines @@
 
 bar1() {
   return "hello";
 }
 
 bar2() {
   return 2;
 }
 """,
 };