Fixed CORE-4102: Bad optimization of OR predicates applied to unions.

git-svn-id: svn+ssh://svn.code.sf.net/p/firebird/code/firebird/branches/B2_5_Release@58099 65644016-39b1-43b1-bf79-96bc8fe82c15
CORE-3993: disable AST delivery at final steps of attachemnt destruction

git-svn-id: svn+ssh://svn.code.sf.net/p/firebird/code/firebird/branches/B2_5_Release@58101 65644016-39b1-43b1-bf79-96bc8fe82c15