Remove array_unique() on expected classes in checkAutoLoadConf()

Remove array_unique() on expected classes in checkAutoLoadConf()

Sometimes classes can be loaded via autoload (PSR-4) and class_aliasing
and due to this calling array_unique() on expected classes will remove
one of these classes due to them sharing the same file (and array_unique()
works on array values).

Also allow for ::class suffixed classes to be namespaced (ie look for \
in the regexes)

Cleanup some of the regexes, remove redunant code (don't need multi cased
letters when we have /i), simplify them

Bug: T206728
Change-Id: I235274d579b1bfd12a448448ddf020546c9aa89b