fixes #27385, implement virtual fields in DDC

tests/language_strong/getters_setters_test.dart

Index: tests/language_strong/getters_setters_test.dart
diff --git a/tests/language_strong/getters_setters_test.dart b/tests/language_strong/getters_setters_test.dart
index 1511e77269453d56f776cab7b316ab37f22eebdf..315da2e958ce8e10ac79004beb09f7e520027ae8 100644
--- a/tests/language_strong/getters_setters_test.dart
+++ b/tests/language_strong/getters_setters_test.dart
@@ -3,6 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import "package:expect/expect.dart";
+import "package:meta/meta.dart" show virtual;
 
 class GettersSettersTest {
 
@@ -61,7 +62,7 @@ class GettersSettersTest {
 }
 
 class A {
-  int x_;
+  @virtual int x_;
   static int foo;
 
   static get bar {