patch 8.2.0599: Netbeans interface insufficiently tested

Problem:    Netbeans interface insufficiently tested.
Solution:   Add more tests. (Yegappan Lakshmanan, closes #5921)
diff --git a/src/os_win32.c b/src/os_win32.c
index 143dab9..6b32869 100644
--- a/src/os_win32.c
+++ b/src/os_win32.c
@@ -2749,6 +2749,10 @@
     void
 mch_exit(int r)
 {
+#ifdef FEAT_NETBEANS_INTG
+    netbeans_send_disconnect();
+#endif
+
 #ifdef VIMDLL
     if (gui.in_use || gui.starting)
 	mch_exit_g(r);