⭐ Isolate settings in factories

[kylekatarnls]

Global setters like setTestNow, serializeUsing, setTranslator etc. are not isolated when called from factories:

CarbonImmutable::setTestNow('1990-07-31 23:59:59');

$libAFactory = new FactoryImmutable();
$libAFactory->setTestNow('2000-02-05 15:20:00');

$libBFactory = new FactoryImmutable();
$libBFactory->setTestNow('2050-12-01 00:00:00');

echo $libAFactory->now() . "\n"; // 2000-02-05 15:20:00
echo $libBFactory->now() . "\n"; // 2050-12-01 00:00:00
echo CarbonImmutable::now() . "\n"; // 1990-07-31 23:59:59

Carbon version: 2.84.1

PHP version: 8.0.0

Expected output:

2000-02-05 15:20:00
2050-12-01 00:00:00
1990-07-31 23:59:59

Current output:

2050-12-01 00:00:00
2050-12-01 00:00:00
2050-12-01 00:00:00