Linux: Stop MidiInputThread before freeing handle in AlsaClient destructor

When immediately closing a MidiInput after starting, the ALSA handle may be closed whilst the MidiInputThread is running and it polls a destroyed handle

modules/juce_audio_devices/native/juce_linux_Midi.cpp

@@ -51,13 +51,13 @@ public:
         jassert (instance != nullptr);
         instance = nullptr;
 
-        if (handle != nullptr)
-            snd_seq_close (handle);
-
         jassert (activeCallbacks.get() == 0);
 
         if (inputThread)
             inputThread->stopThread (3000);
+
+        if (handle != nullptr)
+            snd_seq_close (handle);
     }
 
     static String getAlsaMidiName()