selftests/landlock: Add binaries to .gitignore

Building the test creates binaries 'wait-pipe' and
'sandbox-and-launch' which need to be gitignore'd.

Signed-off-by: Bharadwaj Raju <bharadwaj.raju777@gmail.com>
Link: https://lore.kernel.org/r/20250210161101.6024-1-bharadwaj.raju777@gmail.com
[mic: Sort entries]
Signed-off-by: Mickaël Salaün <mic@digikod.net>

Author: bharadwaj-raju

tools/testing/selftests/landlock/.gitignore

@@ -1,2 +1,4 @@
 /*_test
+/sandbox-and-launch
 /true
+/wait-pipe