t5516: clean up cloned and new-wt in denyCurrentBranch and worktrees test

The 'denyCurrentBranch and worktrees' test creates a 'cloned' and a 'new-wt'
but it doesn't clean them after the test. This makes other tests that use
the same name after this one to fail.

Add test_when_finished to clean them at the end.

Signed-off-by: Pablo Sabater <pabloosabaterr@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t5516-fetch-push.sh

diff --git a/t/t5516-fetch-push.sh b/t/t5516-fetch-push.sh
index f44250c..c40f279 100755
--- a/t/t5516-fetch-push.sh
+++ b/t/t5516-fetch-push.sh
@@ -1792,6 +1792,7 @@
 '
 
 test_expect_success 'denyCurrentBranch and worktrees' '
+	test_when_finished "rm -fr cloned && git worktree remove --force new-wt" &&
 	git worktree add new-wt &&
 	git clone . cloned &&
 	test_commit -C cloned first &&