* (bug 27680) Fix for r82273: wgCanonicalSpecialPageName no longer false when requesting a special page with subpage parameter
The problem is that in this case $wgOut's Title object is not exactely the same $wgTitle because of line 600 of SpecialPage:
$wgTitle = $page->getTitle();
which strips the subpage parameter. Now using SpecialPage::resolveAliasWithSubpage() so that it works in all cases.
Also PHP strikes again for not allowing SpecialPage::resolveAliasWithSubpage( $title->getDBkey() )[0] syntax. YAY :)