Git commits in Moodle 3.7.0 by Trisha Milan

commit fdb9c3217d1e2593ae37d354da6f54132fbb0809
Author: Trisha Milan <trishamilan@catalyst-au.net>
Date:   Tue, 02 Apr 2019 20:17:18 +0800
Tag:    v3.7.0-beta

MDL-64449 core: Added Session lock debugging option

commit 600de03e0588d1e56e2b2aad7a76067bac1b64a9
Author: Trisha Milan <trishamilan@catalyst-au.net>
Date:   Tue, 19 Feb 2019 11:30:53 +0800
Tag:    v3.7.0-beta

MDL-64894 Theme: Fix unable to expand collapsible topics