Remove checks formerly for MySQL server version
Removed these checks instead of fixing them, for the stated reasons:
* initEditCount.php: "instanceof DatabaseMysql" is not a correct way to
check if the database server is MySQL/MariaDB, because DatabaseMysql is
now a subclass of DatabaseMysqlBase, only used as a wrapper around the
deprecated mysql PHP extension (not the newer mysqli extension). The
check was intended for pre-4.1 versions of MySQL, which do not support
subqueries.
The effect of this change is to use single-query mode whenever there is
only one configured database server, even when using the mysqli PHP
extension, which would have been the original intent.
* fixBug20757.php: If the database server is not MySQL/MariaDB, the
$lowerLeft variable would remain undefined. The script was only intended
for use with MySQL, so the check was only necessary in order to support
pre-4.1 versions of MySQL, which require different SQL.
Follows-up
b74f88967bf090af.
Change-Id: I7f32aed4473e5ea39dc40449ddc0af5f9a10df16