Adjust do visit in ExitDetector

pkg/analyzer/test/generated/all_the_rest_test.dart

Index: pkg/analyzer/test/generated/all_the_rest_test.dart
diff --git a/pkg/analyzer/test/generated/all_the_rest_test.dart b/pkg/analyzer/test/generated/all_the_rest_test.dart
index f032daf233d4338cd8a025a0b23165ec1727566a..04481ef7042266613f92abcdc70a153b9ffee23c 100644
--- a/pkg/analyzer/test/generated/all_the_rest_test.dart
+++ b/pkg/analyzer/test/generated/all_the_rest_test.dart
@@ -3483,6 +3483,10 @@ class ExitDetectorTest extends ParserTestCase {
     _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); }");
   }