patch 8.2.0399: various memory leaks

Problem:    Various memory leaks.
Solution:   Avoid the leaks. (Ozaki Kiichi, closes #5803)
diff --git a/src/message.c b/src/message.c
index 0119145..fbddfad 100644
--- a/src/message.c
+++ b/src/message.c
@@ -865,6 +865,7 @@
     char_u *copy = vim_strnsave((char_u *)name, len);
 
     semsg(msg, copy == NULL ? "NULL" : (char *)copy);
+    vim_free(copy);
 }
 
 /*