Revert "multilayer_metadata_test: open output in text mode"

This reverts commit be56876310f699eef8be8c116b8fcfcfe36048b3.

Reason: exclude the layer-specific metadata API from libaom v3.13.0.
Change-Id: I66da903df798eaab61814b8c01f8796985c04066
diff --git a/test/multilayer_metadata_test.cc b/test/multilayer_metadata_test.cc
index faaf75f..42eee3b 100644
--- a/test/multilayer_metadata_test.cc
+++ b/test/multilayer_metadata_test.cc
@@ -163,7 +163,7 @@
       transfer_characteristics: 13
       matrix_coefficients: 6
     )";
-  libaom_test::TempOutFile tmp_file(/*text_mode=*/true);
+  libaom_test::TempOutFile tmp_file;
   fprintf(tmp_file.file(), "%s", metadata.c_str());
   fflush(tmp_file.file());