Add ClosedWorld.elementEnvironment and remove Compiler.elementEnvironment

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.
 
 library compiler_helper;
 
 import 'dart:async';
 import "package:expect/expect.dart";
 
 import 'package:compiler/compiler_new.dart';
@@ skipping 60 matching lines @@
         enableMinification: minify,
         disableInlining: disableInlining,
         trustJSInteropTypeAnnotations: trustJSInteropTypeAnnotations,
         outputProvider: outputCollector);
     await compiler.init();
     compiler.parseScript(code);
     LibraryElement mainApp = compiler.mainApp;
     MethodElement element = mainApp.find(entry);
     if (element == null) return null;
     compiler.phase = Compiler.PHASE_RESOLVING;
-    compiler.processQueue(compiler.enqueuer.resolution, element,
+    compiler.processQueue(
+        compiler.frontendStrategy.elementEnvironment,
+        compiler.enqueuer.resolution,
+        element,
         compiler.libraryLoader.libraries);
     ResolutionWorkItem resolutionWork =
         new ResolutionWorkItem(compiler.resolution, element);
     resolutionWork.run();
     ClosedWorld closedWorld = compiler.closeResolution().closedWorld;
     CodegenWorkItem work =
         new ElementCodegenWorkItem(compiler.backend, closedWorld, element);
     compiler.phase = Compiler.PHASE_COMPILING;
     work.run();
     js.JavaScriptBackend backend = compiler.backend;
@@ skipping 206 matching lines @@
     }
   }
 
   return checker;
 }
 
 RegExp _directivePattern = new RegExp(
     //      \1                     \2        \3
     r'''// *(present|absent): *(?:"([^"]*)"|'([^'']*)')''',
     multiLine: true);