Smoke test collection should not be executable

Since it ended up being a plain text file rather than a script
(post-fix for MDEV-25288)
Also removed main-test_sql_discovery.create from the list,
as a workaround for MDEV-25384. The bug only affects 10.3+,
but it will be simpler if 10.2 part of the tests is the same
in all branches

mysql-test/collections/smoke_test

@@ -42,7 +42,6 @@ innodb_gis.rtree
 innodb_zip.innodb-zip
 innodb_zip.page_size
 json.json_no_table
-main-test_sql_discovery.create
 main.blackhole
 main.bootstrap
 main.compress