Remove support for the DeferredLibrary annotation and remove tests of it

sdk/lib/_internal/lib/js_helper.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.
 
 library _js_helper;
 
 import 'dart:collection';
 import 'dart:_isolate_helper' show
     IsolateNatives,
     leaveJsAsync,
@@ skipping 3213 matching lines @@
 
 typedef Future<Null> LoadLibraryFunctionType();
 
 LoadLibraryFunctionType _loadLibraryWrapper(String loadId) {
   return () => loadDeferredLibrary(loadId);
 }
 
 final Map<String, Future<Null>> _loadingLibraries = <String, Future<Null>>{};
 final Set<String> _loadedLibraries = new Set<String>();
 
-Future<Null> loadDeferredLibrary(String loadId, [String uri]) {
+Future<Null> loadDeferredLibrary(String loadId) {
   List<List<String>> hunkLists = JS('JSExtendableArray|Null',
       '\$.libraries_to_load[#]', loadId);
   if (hunkLists == null) return new Future.value(null);
 
   return Future.forEach(hunkLists, (hunkNames) {
     Iterable<Future<Null>> allLoads =
-        hunkNames.map((hunkName) => _loadHunk(hunkName, uri));
+        hunkNames.map((hunkName) => _loadHunk(hunkName));
     return Future.wait(allLoads).then((_) => null);
   }).then((_) => _loadedLibraries.add(loadId));
 }
 
-Future<Null> _loadHunk(String hunkName, String uri) {
+Future<Null> _loadHunk(String hunkName) {
   // TODO(ahe): Validate libraryName.  Kasper points out that you want
   // to be able to experiment with the effect of toggling @DeferLoad,
   // so perhaps we should silently ignore "bad" library names.
   Future<Null> future = _loadingLibraries[hunkName];
   if (future != null) {
     return future.then((_) => null);
   }
 
-  if (uri == null) {
-    uri = IsolateNatives.thisScript;
-  }
+  String uri = IsolateNatives.thisScript;
+
   int index = uri.lastIndexOf('/');
   uri = '${uri.substring(0, index + 1)}$hunkName';
 
   if (Primitives.isJsshell || Primitives.isD8) {
     // TODO(ahe): Move this code to a JavaScript command helper script that is
     // not included in generated output.
     return _loadingLibraries[hunkName] = new Future<Null>(() {
       try {
         // Create a new function to avoid getting access to current function
         // context.
@@ skipping 80 matching lines @@
   throw new MainError("No top-level function named 'main'.");
 }
 
 void badMain() {
   throw new MainError("'main' is not a function.");
 }
 
 void mainHasTooManyParameters() {
   throw new MainError("'main' expects too many parameters.");
 }