test-bpf-token: convert "intro" to a test

This file was a bit strange… It was shoehorning a manual test into
the intro block and not using the rest of the TEST machinery. Let's
convert it into a normal executable with a run function as we do
in other similar cases.

src/test/test-bpf-token.c

@@ -4,9 +4,10 @@
 #include <fcntl.h>
 
 #include "fd-util.h"
-#include "tests.h"
+#include "main-func.h"
+#include "tests.h"  /* NOLINT(misc-include-cleaner): this is needed conditionally */
 
-static int intro(void) {
+static int run(int argc, char *argv[]) {
 #if defined(LIBBPF_MAJOR_VERSION) && (LIBBPF_MAJOR_VERSION > 1 || (LIBBPF_MAJOR_VERSION == 1 && LIBBPF_MINOR_VERSION >= 5))
         _cleanup_close_ int bpffs_fd = open("/sys/fs/bpf", O_RDONLY);
         if (bpffs_fd < 0)
@@ -16,10 +17,11 @@ static int intro(void) {
         if (token_fd < 0)
                 return log_error_errno(errno, "Failed to create bpf token: %m");
 
-        return EXIT_SUCCESS;
+        log_info("Successfully created token fd.");
+        return 0;
 #else
         return log_tests_skipped("libbpf is older than v1.5");
 #endif
 }
 
-DEFINE_TEST_MAIN_WITH_INTRO(LOG_DEBUG, intro);
+DEFINE_MAIN_FUNCTION_WITH_POSITIVE_FAILURE(run);