fixup! Bugfix: QA: test_node: Ensure debug.log exists at start of ass…

…ert_debug_log

test/functional/test_framework/test_node.py

@@ -511,7 +511,7 @@ def assert_debug_log(self, expected_msgs, unexpected_msgs=None, timeout=2):
         if not self.debug_log_path.exists():
             # File must exist for this to work
             os.makedirs(self.debug_log_path.parent, exist_ok=True)
-            with open(self.debug_log_path, mode='a') as f:
+            with open(self.debug_log_path, mode='a', encoding='utf-8'):
                 pass
 
         time_end = time.time() + timeout * self.timeout_factor