Fix "invalid UTF-8" test failure on Windows

On Windows an extra line "exec: Process pid=... exited with status code 0"
is reported after terminating the subprocess. This isn't relevant for
the `text_exec_invalid_utf` test, so the extra line is just ignored.

No functional changes.

tests/test_runner.py

@@ -145,7 +145,10 @@ class ExecCommandTest(AbstractCommandTest):
                 ),
                 call(f"exec: TERMinating subprocess pid={pid}"),
                 call(decode_err),
-            ]
+            ],
+            # Pass any_order=True to allow for some extra line reported on Windows
+            # but not on Linux ("exec: Process pid=... exited with status code 0")
+            any_order=True,
         )
 
         # The update should NOT contain a new task status -- that is left to the Worker.