pkg/compiler: fix imports

pkg/compiler/lib/src/compile_time_constants.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 dart2js.compile_time_constant_evaluator;
 
-import 'common.dart';
 import 'common/resolution.dart' show Resolution;
 import 'common/tasks.dart' show CompilerTask, Measurer;
+import 'common.dart';
 import 'compiler.dart' show Compiler;
 import 'constant_system_dart.dart';
 import 'constants/constant_system.dart';
 import 'constants/evaluation.dart';
 import 'constants/expressions.dart';
 import 'constants/values.dart';
 import 'core_types.dart' show CoreTypes;
 import 'dart_types.dart';
 import 'elements/elements.dart';
 import 'elements/modelx.dart'
     show FieldElementX, FunctionElementX, ConstantVariableMixin;
+import 'resolution/operators.dart';
 import 'resolution/tree_elements.dart' show TreeElements;
-import 'resolution/operators.dart';
 import 'tree/tree.dart';
+import 'universe/call_structure.dart' show CallStructure;
 import 'util/util.dart' show Link;
-import 'universe/call_structure.dart' show CallStructure;
 
 /// A [ConstantEnvironment] provides access for constants compiled for variable
 /// initializers.
 abstract class ConstantEnvironment {
   /// The [ConstantSystem] used by this environment.
   ConstantSystem get constantSystem;
 
   /// Returns `true` if a value has been computed for [expression].
   bool hasConstantValue(ConstantExpression expression);
 
@@ skipping 1374 matching lines @@
 class _CompilerEnvironment implements Environment {
   final Compiler compiler;
 
   _CompilerEnvironment(this.compiler);
 
   @override
   String readFromEnvironment(String name) {
     return compiler.fromEnvironment(name);
   }
 }