Compute correct names for closures in operator methods.

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 9a24d6570f04dc9476135d3d18fc78c1ef5a7bf8..d438b7871aec1cbc123aa622b28d55966f47af93 100644
--- a/tests/compiler/dart2js/serialization/test_data.dart
+++ b/tests/compiler/dart2js/serialization/test_data.dart
@@ -544,6 +544,24 @@ test() {}
     'c.dart': '''
 ''',
   }, expectedErrorCount: 1),
+
+  const Test('Closure in operator function', const {
+    'main.dart': '''
+import 'a.dart';
+
+main() {
+  test();
+}
+''',
+  }, preserializedSourceFiles: const {
+    'a.dart': '''
+class C {
+  operator ==(other) => () {};
+}
+
+test() => new C() == null;
+''',
+  }),
 ];
 
 class Test {