Skip failing test in test_sys for now

Updating test_sys to CPython 3.14 is beyond the scope of this PR.

Author: fanninpm

Lib/test/test_sys.py

@@ -882,6 +882,7 @@ def test_subinterp_intern_singleton(self):
                     '''))
                 self.assertTrue(sys._is_interned(s))
 
+    @unittest.expectedFailure # TODO: RUSTPYTHON needs update for context_aware_warnings
     def test_sys_flags(self):
         self.assertTrue(sys.flags)
         attrs = ("debug",