Fix some tests and exclude others from CRLF rewriting.

tests/lib/mirrors/method_mirror_source_line_ending_crlf.dart

Index: tests/lib/mirrors/method_mirror_source_line_ending_crlf.dart
diff --git a/tests/lib/mirrors/method_mirror_source_line_ending_crlf.dart b/tests/lib/mirrors/method_mirror_source_line_ending_crlf.dart
index bcf3e64c1f2d6907bb0f89b82eeced936ad9a7ff..d93615cd83b4c6c7644c3e6b0d6db7e4a043212f 100755
--- a/tests/lib/mirrors/method_mirror_source_line_ending_crlf.dart
+++ b/tests/lib/mirrors/method_mirror_source_line_ending_crlf.dart
@@ -2,8 +2,7 @@
 // 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.
 
-// This file is marked executable so source control will preserve the type of
-// line ending.
+// Note: This test relies on CRLF line endings in the source file.
 
 library line_endings.crlf;