improve IN operator predicate coverage

Prompted in part by this user group thread: https://groups.google.com/forum/?utm_medium=email&utm_source=footer#!msg/realm-cocoa/vdbvJCHWqaY/EzyZAawKXdsJ
`XCTAssertEqual(0U, ([[AllTypesObject objectsWhere:@"boolCol IN %@", @[@NO]] count]));`