Author: Andrew Nicols
MDL-72621 admin: Add environment check for admin deprecation
http://git.moodle.org/gw?p=moodle.git;a=commit;h=a96d456b63eda59cfac201d63e7a9d255519349f
http://github.com/moodle/moodle/commit/a96d456b63eda59cfac201d63e7a9d255519349f
+ 3.9 en [iscustomadminwarnings,core_admin]