adjust failing tests from test_unicode*

Author: youknowone

Lib/test/test_unicode.py

@@ -2530,6 +2530,8 @@ def test_free_after_iterating(self):
         support.check_free_after_iterating(self, iter, str)
         support.check_free_after_iterating(self, reversed, str)
 
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
     def test_check_encoding_errors(self):
         # bpo-37388: str(bytes) and str.decode() must check encoding and errors
         # arguments in dev mode