Replace bad_raw_string_negative_test with a multitest

tests/language/bad_raw_string_negative_test.dart

Index: tests/language/bad_raw_string_negative_test.dart
diff --git a/tests/language/bad_raw_string_negative_test.dart b/tests/language/bad_raw_string_negative_test.dart
deleted file mode 100644
index 89b4659e838edb25d917724b0853233f308f67c3..0000000000000000000000000000000000000000
--- a/tests/language/bad_raw_string_negative_test.dart
+++ /dev/null
@@ -1,9 +0,0 @@
-// Copyright (c) 2014, 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.
-
-main() {
-  // Raw String may not contain newline (may not be multi-line).
-  print(r'
-');
-}