patch 8.2.0334: abort called when using test_void()

Problem:    Abort called when using test_void(). (Dominique Pelle)
Solution:   Only give an error, don't abort.
diff --git a/src/proto/message.pro b/src/proto/message.pro
index 5c9ca6c..16c3354 100644
--- a/src/proto/message.pro
+++ b/src/proto/message.pro
@@ -12,6 +12,7 @@
 int emsg(char *s);
 void iemsg(char *s);
 void internal_error(char *where);
+void internal_error_no_abort(char *where);
 void emsg_invreg(int name);
 void emsg_namelen(char *msg, char_u *name, int len);
 char *msg_trunc_attr(char *s, int force, int attr);