Make possible to add priority for given task

[MateuszLeo]

This patch adds possibility to add priority for given task.
It will allow schedule resolving semaphore in order which will be dictated by priority of tasks. Priority with lower number will be executed first.

const s = new Semaphore(1);
function task(priority) {
    const release = await s.acquire(priority);
    release();
}
await Promise.all([task(3), task(1), task(2), task(1)]); //Will execute task in [1, 1, 2, 3] order.