Throw deprecation notices for properties mark as ZEND_ACC_DEPRECATED

PHP doesn't support deprecating properties so we have to overload the
default property handler and lookup the property flags to issue the
warning
PHP-797: Deprecate the properties on MongoClient

They aren't actually used or updated (except for the ->connected, which
is a pain and better alternatives exist already).
PHP-797: Deprecate the exception properties, the getXX() methods should be used
instead
Add a testcase for MongoClient properties, making sure we only deprecate
the property names when they are accessed from valid scopes and don't
act like a dbname
Fix test after deprecating the connected property