Move exception support to its own library

pkg/analyzer/lib/src/task/dart.dart

Index: pkg/analyzer/lib/src/task/dart.dart
diff --git a/pkg/analyzer/lib/src/task/dart.dart b/pkg/analyzer/lib/src/task/dart.dart
index 91cc75586d44168cd4692536fdcd9bd54e21cc80..94cd824eb40cd809d06fac5ce5161a0acf9148fc 100644
--- a/pkg/analyzer/lib/src/task/dart.dart
+++ b/pkg/analyzer/lib/src/task/dart.dart
@@ -11,6 +11,7 @@ import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
+import 'package:analyzer/exception/exception.dart';
 import 'package:analyzer/src/context/cache.dart';
 import 'package:analyzer/src/context/context.dart';
 import 'package:analyzer/src/dart/ast/utilities.dart';
@@ -25,7 +26,6 @@ import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/error.dart';
 import 'package:analyzer/src/generated/error_verifier.dart';
 import 'package:analyzer/src/generated/incremental_resolver.dart';
-import 'package:analyzer/src/generated/java_engine.dart';
 import 'package:analyzer/src/generated/parser.dart';
 import 'package:analyzer/src/generated/resolver.dart';
 import 'package:analyzer/src/generated/sdk.dart';