Fixed equals operator in test.

tests/corelib/list_contains_argument_order_test.dart

Index: tests/corelib/list_contains_argument_order_test.dart
diff --git a/tests/corelib/list_contains_argument_order_test.dart b/tests/corelib/list_contains_argument_order_test.dart
index 4b9eaf23bbff52be2a8eabf98f6084b24cbd4f0d..5f3148c10877c22efcae8f72016725803af12a77 100644
--- a/tests/corelib/list_contains_argument_order_test.dart
+++ b/tests/corelib/list_contains_argument_order_test.dart
@@ -6,13 +6,13 @@ import "package:expect/expect.dart";
 
 class A {
   const A();
-  bool operator ==(A other) {
+  bool operator ==(Object other) {
     return false;
   }
 }
 
 class B {
-  bool operator ==(B other) {
+  bool operator ==(Object other) {
     Expect.fail("Bad equality order.");
   }
 }