There are functions listed in testable facade that don't have a lot of dependencies,
instead mostly just take the input and perform database functions on them.
These can be tested without a testable facade function and so will be removed.
PHPBB3-11620
Make the class functions of testable_facade no longer static methods,
but a class based one and expand the methods to be filled in, in later commits.
PHPBB3-11620
Since many functions in session.php have global variables inside the function,
this exposes those functions through a testable facade that uses testable_factory's
mock global variables to modify global variables used in the functions.
This is using the facade pattern to provide a testable "front" to the functions in sessions.php.
PHPBB3-11620
