[java] ForLoopCanBeForeach should consider iterating on this

[oowekyala]

Affects PMD Version: 6.0.0

Rule: ForLoopCanBeForeach

Description: The rule should report loops that are iterated on this if possible. For now it considers neither this.iterator() nor just iterator(). Followup on #800

Code Sample demonstrating the issue:

import java.util.Iterator;
class Foo<T> implements Iterable<T> {

  @Override
  public Iterator<T> iterator() {
    return null;
  }

  private void fofo() {
    for (Iterator<T> it = iterator(); it.hasNext();) {
      T item = it.next();
    }
    for (Iterator<T> it = this.iterator(); it.hasNext();) {
      T item = it.next();
    }
  }
}

Running PMD through: CLI

[adangel]

This has been fixed with PMD 7.0.0-rc1.