qemurunner: Remove the signal handler before stopping qemu

The qemu shutdown can race with the signal handler removal leading to
confusing tracebacks on slower/loaded systems.

Remove the signal handler first before shutting down.

(From OE-Core rev: 1b63ce7bb83134f84bf07d1075d5ca0d5466ed3d)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/lib/oeqa/utils/qemurunner.py

@@ -350,10 +350,10 @@ class QemuRunner:
         return True
 
     def stop(self):
-        self.stop_thread()
-        self.stop_qemu_system()
         if hasattr(self, "origchldhandler"):
             signal.signal(signal.SIGCHLD, self.origchldhandler)
+        self.stop_thread()
+        self.stop_qemu_system()
         if self.runqemu:
             if hasattr(self, "monitorpid"):
                 os.kill(self.monitorpid, signal.SIGKILL)