Sort detected PersistenceExceptionTranslator beans

[ttddyy]

Apply sorting on detected PersistenceExceptionTranslators.

Relates to #24634

[ttddyy]

The default PersistenceExceptionTranslators, such as AbstractEntityManagerFactoryBean, are not ordered, so they always come last.
For my usecase, I need my custom one to be first, so it is fine. But, if custom translators need to come after defaults, then, default ones need to have some ordering numbers assigned.

[NathanQingyangXu]

I think the above code can be more compact and elegant as

Comparator<Object> comparatorToUse = OrderComparator.INSTANCE;
if (beanFactory instanceof DefaultListableBeanFactory) {
	comparatorToUse = ((DefaultListableBeanFactory) beanFactory).getDependencyComparator();
}

or simply

Comparator<Object> comparatorToUse;
if (beanFactory instanceof DefaultListableBeanFactory) {
	comparatorToUse = ((DefaultListableBeanFactory) beanFactory).getDependencyComparator();
}
else  {
	comparatorToUse = OrderComparator.INSTANCE;
}

[ttddyy]

DefaultListableBeanFactory#getDependencyComparator() is @Nullable, so it might return null.

[jhoeller]

As indicated on #25559, I've resolved this in a different way, calling getBeanProvider with its orderedStream method (which takes the factory-level dependency comparator into account even for @Order definitions on @Bean methods). In order to preserve non-eager init semantics, we're specifically using a new getBeanProvider variant with an explicit allowEagerInit flag there now.

Thanks for the pull request, in any case!