Git commits in Moodle 3.8.6 by Dani Palou

commit efcc68a5ced46712d3fab873824aa91a2d494200
Author: Dani Palou <dani@moodle.com>
Date:   Wed, 23 Sep 2020 17:18:28 +0800
Tag:    v3.8.6

MDL-68098 tests: Reset FILTERLIB_PRIVATE after tests


commit 800f4dfb153d70e10aee60aec387c69b9a0ac327
Author: Dani Palou <dani@moodle.com>
Date:   Fri, 04 Sep 2020 15:25:15 +0800
Tag:    v3.8.6

MDL-68098 ws: Add unit tests to test mathjax in WS


commit 4fc00c4b68e80d295579a1281cbd8d4aec3e5de8
Author: Dani Palou <dani@moodle.com>
Date:   Fri, 04 Sep 2020 15:21:45 +0800
Tag:    v3.8.6

MDL-68098 ws: Fix WebServices broken by filters HTML