patch 8.2.4716: memory allocation failure not tested when defining a function

Problem:    Memory allocation failure not tested when defining a function.
Solution:   Add a test. (Yegappan Lakshmanan, closes #10127)
diff --git a/src/alloc.h b/src/alloc.h
index 58ae25c..651e01f 100644
--- a/src/alloc.h
+++ b/src/alloc.h
@@ -44,5 +44,6 @@
     aid_newwin_wvars,
     aid_newtabpage_tvars,
     aid_blob_alloc,
+    aid_get_func,
     aid_last
 } alloc_id_T;