selftests/bpf: Fix cleanup in check_fd_array_cnt__fd_array_too_big()

The Close() macro uses the passed in expression three times, which
leads to repeated execution in case it has side effects. That is,
Close(i--) would decrement i three times.

ASAN caught a stack-buffer-undeflow error at a point where this was
overlooked. Fix it.

Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Link: https://lore.kernel.org/r/20260223190736.649171-12-ihor.solodrai@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Author: theihor

tools/testing/selftests/bpf/prog_tests/fd_array.c

@@ -412,8 +412,8 @@ static void check_fd_array_cnt__fd_array_too_big(void)
 	ASSERT_EQ(prog_fd, -E2BIG, "prog should have been rejected with -E2BIG");
 
 cleanup_fds:
-	while (i > 0)
-		Close(extra_fds[--i]);
+	while (i-- > 0)
+		Close(extra_fds[i]);
 }
 
 void test_fd_array_cnt(void)