PropertyHandle :: ValidateForParent - Is property handle still valid for parent

The function checks, whether the property handle is still valid for the parent property handle passed to the function, i.e. whether the property is a sub-property of the parent. Since parents may move for transient or weak-typed properties, the application must check in case of subordinated property handles, whether those are still valid or not.

When passing true (YES) for reopen, the property handle automatically reopens the current property handle for the new parent.