TreeEqualityVisitor needs to verify parens

[apmoriarty]

The tree equality visitor will call the following queries equal

((_Bounded = true) && (NUM > '1' && NUM < '5'))
and
(_Bounded = true) && (NUM > '1' && NUM < '5')

The first query is correct. The second query will terminate explosively. Fix the TreeEqualityVisitor so it no longer ignores reference expressions -- at least in the case of QueryPropertyMarker nodes.