Support malformed types

tests/compiler/dart2js/serialization/test_data.dart

Index: tests/compiler/dart2js/serialization/test_data.dart
diff --git a/tests/compiler/dart2js/serialization/test_data.dart b/tests/compiler/dart2js/serialization/test_data.dart
index 950a211e68ada27a20222dedf1b0402ffde3f5b2..562b21d7cf1f3cd0ee213eac2d545aeb7eaf7e6e 100644
--- a/tests/compiler/dart2js/serialization/test_data.dart
+++ b/tests/compiler/dart2js/serialization/test_data.dart
@@ -402,6 +402,20 @@ class A {
 }
 ''',
   }),
+
+  const Test('Malformed types', const {
+    'main.dart': '''
+import 'a.dart';
+
+main() {
+  m();
+}
+''',
+  }, preserializedSourceFiles: const {
+    'a.dart': '''
+Unresolved m() {}
+''',
+  }),
 ];
 
 class Test {