Adjust do visit in ExitDetector

pkg/analyzer/test/generated/all_the_rest_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.all_the_rest_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/dart/element/type.dart';
@@ skipping 3465 matching lines @@
   }
 
   void test_creation() {
     expect(new ExitDetector(), isNotNull);
   }
 
   void test_doStatement_throwCondition() {
     _assertTrue("{ do {} while (throw ''); }");
   }
 
+  void test_doStatement_return() {
+    _assertTrue("{ do { return null; } while (1 == 2); }");
+  }
+
   void test_doStatement_true_break() {
     _assertFalse("{ do { break; } while (true); }");
   }
 
   void test_doStatement_true_continue() {
     _assertTrue("{ do { continue; } while (true); }");
   }
 
   void test_doStatement_true_if_return() {
     _assertTrue("{ do { if (true) {return null;} } while (true); }");
@@ skipping 808 matching lines @@
     expect(UriKind.fromEncoding(0x70), same(UriKind.PACKAGE_URI));
     expect(UriKind.fromEncoding(0x58), same(null));
   }
 
   void test_getEncoding() {
     expect(UriKind.DART_URI.encoding, 0x64);
     expect(UriKind.FILE_URI.encoding, 0x66);
     expect(UriKind.PACKAGE_URI.encoding, 0x70);
   }
 }