Fix newline normalization in _PhysicalFile.readAsStringSync().

pkg/analyzer/lib/file_system/physical_file_system.dart

Index: pkg/analyzer/lib/file_system/physical_file_system.dart
diff --git a/pkg/analyzer/lib/file_system/physical_file_system.dart b/pkg/analyzer/lib/file_system/physical_file_system.dart
index 18694c09e4b95615516b41c6eb0816ad252f8aba..e7a83a41c4fe55b4692b1f059379e6cfbdc5347c 100644
--- a/pkg/analyzer/lib/file_system/physical_file_system.dart
+++ b/pkg/analyzer/lib/file_system/physical_file_system.dart
@@ -114,7 +114,7 @@ class _PhysicalFile extends _PhysicalResource implements File {
   String readAsStringSync() {
     try {
       io.File file = _entry as io.File;
-      return file.readAsStringSync();
+      return FileBasedSource.fileReadMode(file.readAsStringSync());
     } on io.FileSystemException catch (exception) {
       throw new FileSystemException(exception.path, exception.message);
     }