[testlib] put postgres test database in test/data/database directory
with other (sqlite) test databases. Closes #9240765
Simplify .hgignore in passing.
ifnotrql('CWConstraintType X WHERE X name "RQLUniqueConstraint"',ask_confirm=False):rql('INSERT CWConstraintType X: X name "RQLUniqueConstraint"',ask_confirm=False)