ErrAliasReferRoot and WarnAliasReferRootHierarchy are only shown when code has correct order

This is throwing the ErrAliasReferRoot error

Item {
    id: root
    property alias test: root
}

but this isn't

Item {
    property alias test: root
    id: root
}

The error check in qmljscheck currently depends on the order in which property and id definitions are. If the Item doesn't start with an id the check for alias referencing root id isn't working as the id stack is empty at the point of checking.