DynamicReturnTypeExtensionRegistry: Cache extension-class-names

[staabm]

/Users/staabm/workspace/phpstan-src/bin/phpstan analyze -vvv --debug /Users/staabm/workspace/shopware/src/Core/Framework/DependencyInjection/Configuration.php on shopware/shopware@5010d1c

before this PR:
3,5s 190.5 MB

after this PR:
2,7s 188.5 MB

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prevents expensive repetetive calls to getParentClass()/getParentClassNames()

[phpstan-bot]

This pull request has been marked as ready for review.

[staabm]

we have a similar code in

phpstan-src/src/Analyser/TypeSpecifier.php

Line 795 in be4165f

foreach (array_merge([$className], $class->getParentClassesNames(), $class->getNativeReflection()->getInterfaceNames()) as $extensionClassName) {

and

phpstan-src/src/Analyser/ExprHandler/Helper/EarlyTerminatingCallHelper.php

Line 61 in be4165f

foreach (array_merge([$referencedClass], $classReflection->getParentClassesNames(), $classReflection->getNativeReflection()->getInterfaceNames()) as $className) {

but I did not yet have evidence this is similar slow.

[ondrejmirtes]

Also in LazyRegistry and Collectors\Registry.

[staabm]

LazyRegistry and Collectors\Registry.

those depend on runtime reflection, while the other ones depend on static reflection.

should I switch them to make use of ReflectionProvider?