Switch atomic test and set API from __sync to __atomic builtin
__sync_test_and_set uses full memory barriers for AArch64,
__atomic_exchange(ACQUIRE) would use load acquire.
#define clib_atomic_cmp_and_swap(addr,old,new) __sync_val_compare_and_swap(addr, old, new)
#define clib_atomic_bool_cmp_and_swap(addr,old,new) __sync_bool_compare_and_swap(addr, old, new)
-#define clib_atomic_test_and_set(a) __sync_lock_test_and_set(a, 1)
+#define clib_atomic_test_and_set(a) __atomic_exchange_n(a, 1, __ATOMIC_ACQUIRE)
#define clib_atomic_release(a) __sync_lock_release(a)
#define clib_atomic_fence_rel() __atomic_thread_fence(__ATOMIC_RELEASE);
