selftests/bpf: Add ASSERT_OK_FD macro

Add a new dedicated ASSERT macro ASSERT_OK_FD to test whether a socket
FD is valid or not. It can be used to replace macros ASSERT_GT(fd, 0, ""),
ASSERT_NEQ(fd, -1, "") or statements (fd < 0), (fd != -1).
Suggested-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
Link: https://lore.kernel.org/r/ded75be86ac630a3a5099739431854c1ec33f0ea.1720515893.git.tanggeliang@kylinos.cnSigned-off-by: Martin KaFai Lau <martin.lau@kernel.org>

tools/testing/selftests/bpf/test_progs.h

@@ -377,6 +377,15 @@ int test__join_cgroup(const char *path);
 	___ok;								\
 })
 
+#define ASSERT_OK_FD(fd, name) ({					\
+	static int duration = 0;					\
+	int ___fd = (fd);						\
+	bool ___ok = ___fd >= 0;					\
+	CHECK(!___ok, (name), "unexpected fd: %d (errno %d)\n",		\
+	      ___fd, errno);						\
+	___ok;								\
+})
+
 #define SYS(goto_label, fmt, ...)					\
 	({								\
 		char cmd[1024];						\