fix(java): reproduce silent Set child-loss for package-private nodes

[PiotrDuz]

cyclic graphs

Wide fan-out (one parent, many children) cyclic graph of package-private nodes loses entries from a Set field on deserialize - no exception.

Why?

fory had a regression bug of cyclic graph losing edges. Want to pin it so no further regressions are possible.

What does this PR do?

This PR adds a test case that reproduces the regression

Related issues

#3903

AI Contribution Checklist

The test has been generated by AI, but the idea and guidance is human - the problem and its reporduction in version 1.1.0 is tested by hand.

[wenshao]

[Critical] PR adds a test that reproduces an active bug (issue #3903) but contains no production code fix. CI confirms all Java jobs fail (Java CI 8/11/17/21/25/26, Openj9, Windows, Code Style Check). Merging would break main with a permanently failing test. The fix(java): commit type signals a bug fix but delivers only a regression test. Either include the production fix, mark the test @ignore with a link to #3903, or change the commit type to test.

— qwen3.8-max-preview via Qwen Code /review

[chaokunyang]

After reviewing this issue, cyclic references should not be used as Set elements or Map keys. Fory must publish an object reference before all of its fields have been fully deserialized in order to resolve cycles. If that partially materialized object is inserted into a hash-based container, hashCode() or equals() may observe incomplete state. When the remaining fields are restored, the hash may change and invalidate the container's internal structure.

This happened to work previously because the relevant List or collection field was serialized and deserialized last, after the fields used by hashCode() and equals() had already been restored. That ordering was incidental and is no longer guaranteed after the field-ordering semantics were adjusted.

The recommended workaround is to serialize the cyclic references as a List, mark the derived Set as transient, and materialize the Set lazily after deserialization:

private List<Node> parentList = new ArrayList<>();
private transient Set<Node> parents;

public Set<Node> getParents() {
  if (parents == null) {
    parents = new LinkedHashSet<>(parentList);
  }
  return parents;
}

The same approach can be used for maps by serializing an ordered list of key-value entries and constructing the map after the object graph has been fully deserialized. Lists, arrays, object fields, and map values may still contain cyclic references; the limitation applies specifically to cyclic objects used as set elements or map keys.