tests/ktest_netlink_message_writer: remove INVARIANTS requirement

INVARIANTS is meant to be used to enable extra sanity checking for
internal structures, not enable/disable tests in the freebsd kyua
test suite.

STABLE branches include a GENERIC kernconf without INVARIANTS, so
ktest_netlink_message_writer is broken on such branches:

https://ci.freebsd.org/job/FreeBSD-stable-15-amd64-test/253/testReport/sys.netlink.test_netlink_message_writer/py/__test_cases_list__/

Reviewed by:	lwhsu, imp
Approved by:	lwhsu (mentor)
Pull Request:	https://github.com/freebsd/freebsd-src/pull/1889
MFC after:	3 days
Signed-off-by:	Siva Mahadevan <siva@FreeBSD.org>
Sponsored by:	The FreeBSD Foundation

sys/netlink/ktest_netlink_message_writer.c

@@ -37,8 +37,6 @@
 #define KTEST_CALLER
 #include <netlink/ktest_netlink_message_writer.h>
 
-#ifdef INVARIANTS
-
 struct test_nlbuf_attrs {
 	uint32_t	size;
 	uint32_t	expected_avail;
@@ -98,16 +96,13 @@ test_nlbuf_writer_allocation(struct ktest_test_context *ctx)
 
 	return (0);
 }
-#endif
 
 static const struct ktest_test_info tests[] = {
-#ifdef INVARIANTS
 	{
 		.name = "test_nlbuf_writer_allocation",
 		.desc = "test different buffer sizes in the netlink writer",
 		.func = &test_nlbuf_writer_allocation,
 		.parse = &test_nlbuf_parser,
 	},
-#endif
 };
 KTEST_MODULE_DECLARE(ktest_netlink_message_writer, tests);

sys/netlink/ktest_netlink_message_writer.h

@@ -28,7 +28,7 @@
 #ifndef _NETLINK_KTEST_NETLINK_MESSAGE_WRITER_H_
 #define _NETLINK_KTEST_NETLINK_MESSAGE_WRITER_H_
 
-#if defined(_KERNEL) && defined(INVARIANTS)
+#if defined(_KERNEL)
 
 bool nlmsg_get_buf_wrapper(struct nl_writer *nw, size_t size, bool waitok);