[LibOS/regression] Fix syscall arguments in futex test

LibOS/shim/test/regression/futex.c

@@ -20,7 +20,7 @@ static int myfutex = 0;
 
 static int futex(int* uaddr, int futex_op, int val, const struct timespec* timeout, int* uaddr2,
                  int val3) {
-    return syscall(SYS_futex, uaddr, futex_op, val, timeout, uaddr, val3);
+    return syscall(SYS_futex, uaddr, futex_op, val, timeout, uaddr2, val3);
 }
 
 void* thread_function(void* argument) {