refactor(optimize): getMultipleRunDates method

[oleksiikhr]

Hi, it seems to me here CronExpression@getMultipleRunDates we can speed up the results. From the last received date, calculate the next one without using $nth.

public function testPerformance(): void
{
    $start = microtime(true);

    for ($i = 0; $i < 10; $i++) {
        $cron = CronExpression::factory('*/2 * * * *');
        $cron->getMultipleRunDates(200, 'now', false, true);
    }

    $this->assertTrue(true);

    // Before: ~1.3. After: ~0.025
    die(microtime(true) - $start);
}

For verification, I added the changes to the new method and checked this way:

public function testCompare(): void
{
    $cron = CronExpression::factory('* * * * *');
    $this->assertEquals(
        $cron->getMultipleRunDates(50, '2008-11-09 00:05:00', true, true),
        $cron->getMultipleRunDates2(50, '2008-11-09 00:05:00', true, true)
    );
    $this->assertEquals(
        $cron->getMultipleRunDates(50, '2008-11-09 00:05:00', false, false),
        $cron->getMultipleRunDates2(50, '2008-11-09 00:05:00', false, false)
    );
    $this->assertEquals(
        $cron->getMultipleRunDates(50, '2008-11-09 00:05:00', false, true),
        $cron->getMultipleRunDates2(50, '2008-11-09 00:05:00', false, true)
    );
    $this->assertEquals(
        $cron->getMultipleRunDates(50, '2008-11-09 00:05:00', true, false),
        $cron->getMultipleRunDates2(50, '2008-11-09 00:05:00', true, false)
    );

    $cron = CronExpression::factory('1 1 * 3 1');
    $this->assertEquals(
        $cron->getMultipleRunDates(50, '2009-05-03 13:15:25', true, true),
        $cron->getMultipleRunDates2(50, '2009-05-03 13:15:25', true, true)
    );
    $this->assertEquals(
        $cron->getMultipleRunDates(50, '2009-05-03 13:15:25', false, false),
        $cron->getMultipleRunDates2(50, '2009-05-03 13:15:25', false, false)
    );
    $this->assertEquals(
        $cron->getMultipleRunDates(50, '2009-05-03 13:15:25', false, true),
        $cron->getMultipleRunDates2(50, '2009-05-03 13:15:25', false, true)
    );
    $this->assertEquals(
        $cron->getMultipleRunDates(50, '2009-05-03 13:15:25', true, false),
        $cron->getMultipleRunDates2(50, '2009-05-03 13:15:25', true, false)
    );
}

And, it seems working :)

[dragonmantank]

Thanks!