Fix handling of CRLF line endings in Script::GetSnippet.

tests/lib/mirrors/method_mirror_source_line_ending_lf.dart

Index: tests/lib/mirrors/method_mirror_source_line_ending_lf.dart
diff --git a/tests/compiler/dart2js/path with spaces/file with spaces.dart b/tests/lib/mirrors/method_mirror_source_line_ending_lf.dart
old mode 100644
new mode 100755
similarity index 55%
copy from tests/compiler/dart2js/path with spaces/file with spaces.dart
copy to tests/lib/mirrors/method_mirror_source_line_ending_lf.dart
index b0cc20402f823946fa54730f2bb581c9bf58365a..71a34c82d29a17993417f8641a1bc38e63e5f11f
--- a/tests/compiler/dart2js/path with spaces/file with spaces.dart	
+++ b/tests/lib/mirrors/method_mirror_source_line_ending_lf.dart
@@ -2,8 +2,15 @@
 // 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.
 
-import 'library space/lib with spaces.dart';
+// This file is marked executable so source control will preserve the type of
+// line ending.
 
-main() {
-  if (foo() != 499) throw "bad value";
+library line_endings.lf;
+
+oneLineLF(x) => x;
+multiLineLF(y) {
+  return y + 1;
+}
+a
+(){
 }