selftests/core: fix close_range_test build after XFAIL removal

selftests/core: fix close_range_test build after XFAIL removal

XFAIL was removed in commit 6ecdcc2b6801 ("selftests/harness: Refactor
XFAIL into SKIP") and its use in close_range_test was already replaced
by commit 8232d6627533 ("selftests: core: use SKIP instead of XFAIL in
close_range_test.c"). However, commit ae1e781cd3e9 ("selftests: core:
add tests for CLOSE_RANGE_CLOEXEC") introduced usage of XFAIL in
TEST(close_range_cloexec). Use SKIP there as well.

Fixes: ae1e781cd3e9 ("selftests: core: add tests for CLOSE_RANGE_CLOEXEC")
Cc: Giuseppe Scrivano <gscrivan@redhat.com>
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/r/20201218112428.13662-1-tklauser@distanz.ch
Link: https://lore.kernel.org/r/20201218145415.801063-1-christian.brauner@ubuntu.com
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>