Author: meirzamoodle
MDL-81480 core: Sets user-level session storage functions
Also added @runInSeparateProcess on each session Redis cluster test to let the test run
in a separate process to avoid the error "the headers are not already sent" by PHPUnit.
http://git.moodle.org/gw?p=moodle.git;a=commit;h=c9cb89323cfbb4dbf94abfbae65a8911dd6bec58
http://github.com/moodle/moodle/commit/c9cb89323cfbb4dbf94abfbae65a8911dd6bec58
+ 4.4 en [redissessionhandlerproblem,core_error]