Added dead process test program

dev/uninterruptible.c

@@ -0,0 +1,9 @@
+# Create a process in uninterruptible sleep state that forks a child process.
+# Killing child process will change childs's state to zombie.
+# Useful for WaitforTaskCompletion tests
+
+int main() {
+    vfork();
+    sleep(180);
+    return 0;
+}