python: py-spy: Use SIGKILL to stop it (#180)

See py-spy commit benfred/py-spy@290584d,
SIGINT just raises a flag telling it to stop (makes sense, since it still dumps output etc).
But if py-spy is stuck for whatever reason, it won't be stopped by this signal.

SIGKILL is not handled by py-spy, duh, so it will exit immediately.

Author: Jongy

gprofiler/profilers/python.py

@@ -71,7 +71,7 @@ def _profile_process(self, process: Process) -> Optional[StackToSampleCount]:
                 self._make_command(process.pid, local_output_path),
                 stop_event=self._stop_event,
                 timeout=self._duration + self._EXTRA_TIMEOUT,
-                kill_signal=signal.SIGINT,
+                kill_signal=signal.SIGKILL,
             )
         except ProcessStoppedException:
             raise StopEventSetException