uORBTest_UnitTest: Split test function in 3 separate functions and add a

test which fails because it does the subscription before the advertisement.

src/modules/uORB/uORBTest_UnitTest.hpp

@@ -82,10 +82,15 @@ private:
 	UnitTest(const uORBTest::UnitTest &) {};
 	static int pubsubtest_threadEntry(char *const argv[]);
 	int pubsublatency_main(void);
+	//
 	bool pubsubtest_passed;
 	bool pubsubtest_print;
 	int pubsubtest_res = OK;
 
+	int test_single();
+	int test_multi();
+	int test_multi_reversed();
+
 	int test_fail(const char *fmt, ...);
 	int test_note(const char *fmt, ...);
 };