vim-patch:8.2.3330: Coverity reports using uninitialized field

Problem:    Coverity reports using uninitialized field.
Solution:   Initialize the field early.
7deb4115ef

src/nvim/tag.c

@@ -1467,6 +1467,7 @@ find_tags(
 
   help_save = curbuf->b_help;
   orgpat.pat = pat;
+  orgpat.regmatch.regprog = NULL;
   vimconv.vc_type = CONV_NONE;
 
   /*