[NETBEANS-5659] Collection.forEach is always a read from the collection.

[lahodaj]

Having code like:

List<String> l = new ArrayList<>();
l.add("");
l.forEach(e -> {});

will mark the List as unbalanced - only written to, never read. The hint lists the forEach method in the list of read methods, but for (ordinary) read methods, the hint also requires the return value of the read method to be used. forEach is a bit different in this regard, it runs the lambda for the elements, but does not return anything.

This PR introduces a new STANDALONE_READ_METHODS, which do not require their return value to be used.

It also adds the JEP 431: Sequenced Collections from JDK 21 method names.

Filling with NB20 and against delivery, but no strong opinions on this. I am fine with moving this to master/NB21.

[mbien]

makes sense to me.

+1 for getting this into NB 20, since a hint like this is independent from everything else and should have low risk of causing side effects.

(edit: although I tried to do this once too for the very same hint and it broke a few things #4580 :), but this change here is simpler)