Remove code supporting incremental compilation in dart2js

pkg/compiler/lib/src/apiimpl.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 leg_apiimpl;
 
 import 'dart:async';
 
 import 'package:package_config/packages.dart';
 import 'package:package_config/packages_file.dart' as pkgs;
@@ skipping 208 matching lines @@
     if (resolvedUriTranslator.isNotSet) {
       future = future.then((_) {
         return platform_configuration
             .load(options.platformConfigUri, provider)
             .then((Map<String, Uri> mapping) {
           resolvedUriTranslator.resolvedUriTranslator =
               new ResolvedUriTranslator(mapping, reporter);
         });
       });
     }
+    // TODO(johnniwinther): This does not apply anymore.
     // The incremental compiler sets up the sdk before run.
     // Therefore this will be called a second time.
     return future;
   }
 
   Future<bool> run(Uri uri) {
     Duration setupDuration = measurer.wallClock.elapsed;
     return selfTask.measureSubtask("CompilerImpl.run", () {
       log('Using platform configuration at ${options.platformConfigUri}');
 
@@ skipping 156 matching lines @@
   }
 }
 
 /// For every 'dart:' library, a corresponding environment variable is set
 /// to "true". The environment variable's name is the concatenation of
 /// this prefix and the name (without the 'dart:'.
 ///
 /// For example 'dart:html' has the environment variable 'dart.library.html' set
 /// to "true".
 const String _dartLibraryEnvironmentPrefix = 'dart.library.';