Bug#1121518: mutter: autopkgtest 'installed-tests' is flaky

[Luca Boccassi]

Source: mutter
Version: 49.2-1
User: debian-ci at lists.debian.org
Usertags: flaky
Severity: grave
Justification: flaky autopkgtests are RC as per RT and block other packages

Dear Maintainer(s),

The installed-tests autopkgtest test for mutter are very flaky, and
often fail on all architectures.

A few examples:

mutter-17/wayland-unit.test
https://ci.debian.net/packages/m/mutter/testing/amd64/66626266/#S14
mutter-17/wayland-keyboard.test
https://ci.debian.net/packages/m/mutter/testing/i386/66625005/#S14
mutter-17/wayland-keyboard.test
https://ci.debian.net/packages/m/mutter/testing/arm64/66624922/#S14

As per RT, flaky autopkgtests that fail often are RC.