mtests for master branch fail

Since about a week all master builds fail the mtests (on Travis CI).
Culprit is one of 5dabcda (unlikely), d5a5d6a (unlikely), f1ae341 (most likely), 83310d3 (unlikely) or 4cc2798 (very unlikely)
The error is:

52/62 Test #53: tst_scripting ....................***Failed 2.31 sec
QML debugging is enabled. Only use this in a safe environment.
This plugin does not support createPlatformOpenGLContext!
--- /home/travis/build/musescore/MuseScore/mtest/scripting/p1.log.ref 2020-09-22 09:18:06.892073667 +0000
+++ p1.log 2020-09-22 09:53:52.422398748 +0000
@@ -1,16 +0,0 @@
-test script p1: read score elements
-found:Clef (20) at 0
-found:KeySig (21) at 0
-found:TimeSig (23) at 0
-found:Chord (93) at 0
- beamMode:0
- small:false
- stemDirection:AUTO
- duration:1/4
-found:Rest (24) at 480
-found:Chord (93) at 960
- beamMode:0
- small:false
- stemDirection:AUTO
- duration:1/2
-found:BarLine (11) at 1920