All the setup/teardown/pre/post/conditions template methods
now are required to return void. This was warned with phpunit 7
and now is enforced.
At the same time, fix a few wrong function names,
provider data and param types, return statements...
Four core library classes renamed for autoloading with deprecated stubs
have been converted to the new scheme for autoloading.
They are:
* textlib
* collatorlib
* plugin_manager
* plugininfo_base
These will be removed in 2.9 by MDL-46124