APIdoc for TestFilter should mention necessity to implement .equals() method

Javatest Harness has a public API class com.sun.javatest.TestFilter that test suite developers may use to implement their own test filters.

Javadoc for this class should mention a strong recommendation to override and implement property .equals(Object) (and thus - .hashCode()) methods.

This is necessary because Harness later may call for .equals() to test if thisFilter is equal to otherFilter. Depending on this comparison Harness then makes some functional decisions. For example it may trigger refresh of the Tree if it suspects filters were changed.
See usages of com.sun.javatest.CompositeFilter.equals(TestFilter[], TestFilter[]) method for usecases.