t-reftable-block: mark unused argv/argc

This is conceptually the same as the cases in df9d638 (unit-tests:
ignore unused argc/argv, 2024-08-17), but this unit test was migrated
from the reftable tests in a parallel branch.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: peff

t/unit-tests/t-reftable-block.c

@@ -359,7 +359,7 @@ static void t_index_block_read_write(void)
 		reftable_record_release(&recs[i]);
 }
 
-int cmd_main(int argc, const char *argv[])
+int cmd_main(int argc UNUSED, const char *argv[] UNUSED)
 {
 	TEST(t_index_block_read_write(), "read-write operations on index blocks work");
 	TEST(t_log_block_read_write(), "read-write operations on log blocks work");