merge with 3.23 to get for overrun in ISAM tables with man fields and a blob.

isam/open.c:
  Auto merged
myisam/mi_open.c:
  Auto merged
myisam/mi_dynrec.c:
  merge
mysql-test/r/isam.result:
  merge
mysql-test/t/isam.test:
  merge

isam/open.c

@@ -415,6 +415,9 @@ static void setup_functions(register ISAM_SHARE *share)
     share->read_rnd=_nisam_read_rnd_dynamic_record;
     share->delete_record=_nisam_delete_dynamic_record;
     share->compare_record=_nisam_cmp_dynamic_record;
+
+    /* add bits used to pack data to pack_reclength for faster allocation */
+    share->base.pack_reclength+= share->base.pack_bits;
     if (share->base.blobs)
     {
       share->update_record=_nisam_update_blob_record;