lib/torture: directly remove the dummy signal event again to avoid flapping tests

lib/torture: directly remove the dummy signal event again to avoid flapping tests

I don't know why but commit 57a57a189bd9a7348656990b2c888a328b524bb0:

 lib/torture: assert that a test doesn't create new talloc children of context->ev

introduced the regression thad lead to commit 3fa94d9f2fcb165d435c62badde9e3c8569ff40d:

 selftest: mark samba4.rpc.samr.passwords.lockout on ncacn_np with .samr.lockout as flapping

Doing a TALLOC_FREE(dummy_se) still means we have the
tevent_add_fd() from tevent_common_wakeup_init() cached as
talloc child of tevent_context and that is all we need here
and the test is not flagging anymore.

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>
Autobuild-User(master): Stefan Metzmacher <metze@samba.org>
Autobuild-Date(master): Mon Jun  2 19:13:27 UTC 2025 on atb-devel-224