Support PHPStan 1.7.0

[simPod]

Current autoloading scheme is broken on phpstan 1.7.0 since it does not run code anymore (uses static reflection)

Specifically, it now reports Call to an undefined static method My\Ns\ATest::assertArraySubset() because this trait exists https://github.com/rdohms/phpunit-arraysubset-asserts/blob/master/src/ArraySubsetAssertsEmpty.php

[rdohms]

It looks like PHPStan fixed this on their end. If this is not the case @simPod, please re-open so we can figure out what can be done.