[Regr:6.5->6.6] QDateTime comparison performance regression on macOS

#include <QTest>
#include <QDateTime>
#include <QTimeZone>

class DateTimeBenchmark : public QObject{
	Q_OBJECT
private slots:
	void equal();
};

void DateTimeBenchmark::equal()
{
	constexpr int iterations = 1000;
	constexpr int listSize = 100;

	QVector<QDateTime> list;
	list.reserve(listSize);

	// Init each list entry with random time within the next 60 days and random time zone
	const QDateTime start = QDateTime::currentDateTime();
	const QDateTime end = QDateTime::currentDateTime().addDays(60);
	const auto availableTimeZones = QTimeZone::availableTimeZoneIds();

	std::srand(12345);
	for(int i = 0; i < listSize; ++i)
	{
		QDateTime dateTime = start.addMSecs(std::rand() % start.msecsTo(end));
		QTimeZone timeZone{availableTimeZones.at(std::rand() % availableTimeZones.size())};
		dateTime.setTimeZone(timeZone);
		list.push_back(dateTime);
	}

	// Minimum date for SQL server
	QDateTime emptyQDateTime{QDate{1753, 1, 1}, QTime{0, 0, 0, 0}};

	QBENCHMARK {
		for(int iter = 0; iter < iterations; ++iter)
		{
			for(const auto& t : list)
			{
				bool result = t == emptyQDateTime;
				Q_UNUSED(result);
			}
		}
	}
}

QTEST_GUILESS_MAIN(DateTimeBenchmark);

#include "bench.moc"