Move dart2js from sdk/lib/_internal/compiler to pkg/compiler

pkg/compiler/lib/src/inferrer/simple_types_inferrer.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 simple_types_inferrer;
 
 import '../closure.dart' show ClosureClassMap, ClosureScope;
 import '../dart_types.dart'
     show DartType, InterfaceType, FunctionType, TypeKind;
 import '../elements/elements.dart';
@@ skipping 1324 matching lines @@
     }
 
     handlePlainAssignment(identifier, element, selector,
                           receiverType, currentType,
                           node.expression);
     return handleLoop(node, () {
       visit(node.body);
     });
   }
 }