Move exception support to its own library

pkg/analyzer/test/generated/incremental_resolver_test.dart

 // Copyright (c) 2014, 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 analyzer.test.generated.incremental_resolver_test;
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/element/element.dart';
+import 'package:analyzer/exception/exception.dart';
 import 'package:analyzer/src/context/cache.dart';
 import 'package:analyzer/src/dart/ast/utilities.dart';
 import 'package:analyzer/src/dart/element/element.dart';
 import 'package:analyzer/src/dart/scanner/reader.dart';
 import 'package:analyzer/src/dart/scanner/scanner.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/error.dart';
 import 'package:analyzer/src/generated/incremental_logger.dart' as logging;
 import 'package:analyzer/src/generated/incremental_resolution_validator.dart';
 import 'package:analyzer/src/generated/incremental_resolver.dart';
@@ skipping 2328 matching lines @@
   void logException(Object exception, [Object stackTrace]) {
     lastException = exception;
     lastStackTrace = stackTrace;
   }
 
   @override
   logging.LoggingTimer startTimer() {
     return new logging.LoggingTimer(this);
   }
 }