Fix type inference for self-recursive functions

tests/compiler/dart2js/compiler_helper.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.
 // Test constant folding.
 
 #library("compiler_helper");
 
 #import("dart:uri");
 #import("../../../lib/compiler/implementation/leg.dart", prefix: "leg");
 #import("../../../lib/compiler/implementation/elements/elements.dart", prefix: "lego");
 #import('../../../lib/compiler/implementation/source_file.dart');
 #import("../../../lib/compiler/implementation/ssa/ssa.dart", prefix: "ssa");
 #import("parser_helper.dart");
 #import("mock_compiler.dart");
 
 String compile(String code, [String entry = 'main']) {
   MockCompiler compiler = new MockCompiler();
   compiler.parseScript(code);
   lego.Element element = compiler.mainApp.find(buildSourceString(entry));
   if (element === null) return null;
   compiler.processQueue(compiler.enqueuer.resolution, element);
   leg.WorkItem work = new leg.WorkItem(element, null);
-  String generated = work.run(compiler, compiler.enqueuer.codegen);
-  return generated;
+  work.run(compiler, compiler.enqueuer.codegen);
+  return compiler.enqueuer.codegen.lookupCode(element);
 }
 
 MockCompiler compilerFor(String code, Uri uri) {
   MockCompiler compiler = new MockCompiler();
   compiler.sourceFiles[uri.toString()] = new SourceFile(uri.toString(), code);
   return compiler;
 }
 
 String compileAll(String code) {
   Uri uri = new Uri.fromComponents(scheme: 'source');
@@ skipping 30 matching lines @@
   String generated = compile(code, entry);
   Expect.isTrue(regexp.hasMatch(generated),
                 '"$generated" does not match /$regexp/');
 }
 
 void compileAndDoNotMatch(String code, String entry, RegExp regexp) {
   String generated = compile(code, entry);
   Expect.isFalse(regexp.hasMatch(generated),
                  '"$generated" has a match in /$regexp/');
 }