patch 9.0.1701: vim9 crash when class member overridden

Problem: vim9 crash when class member overridden
Solution: Use method_count field instead

closes: #12676
closes: #12677

Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: Yegappan Lakshmanan <yegappan@yahoo.com>
diff --git a/src/vim9class.c b/src/vim9class.c
index 12b0967..18f36bd 100644
--- a/src/vim9class.c
+++ b/src/vim9class.c
@@ -897,7 +897,7 @@
 		    if (!done && extends_cl != NULL)
 		    {
 			for (int cl_i = 0;
-			     cl_i < extends_cl->class_obj_member_count; ++cl_i)
+			     cl_i < extends_cl->class_obj_method_count; ++cl_i)
 			{
 			    if (STRCMP(ifcl->class_obj_methods[if_i]->uf_name,
 				   extends_cl->class_obj_methods[cl_i]->uf_name)