Migrate the language tests up to arithmetic_test.

tests/language/accessor_conflict_export_test.dart

Index: tests/language/accessor_conflict_export_test.dart
diff --git a/tests/language/accessor_conflict_export_test.dart b/tests/language/accessor_conflict_export_test.dart
deleted file mode 100644
index bac516c16d9b3684d9b780be8daf080decbcb235..0000000000000000000000000000000000000000
--- a/tests/language/accessor_conflict_export_test.dart
+++ /dev/null
@@ -1,18 +0,0 @@
-// Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-// Verify that a getter and its corresponding setter can be imported from two
-// different files via a common export.  In this test the getter is imported
-// first.
-
-import "package:expect/expect.dart";
-
-import "accessor_conflict_export_helper.dart";
-
-main() {
-  getValue = 123;
-  Expect.equals(x, 123);
-  x = 456;
-  Expect.equals(setValue, 456);
-}