autopkgtest fails frequently in groovy on armhf

https://autopkgtest.ubuntu.com/packages/s/snapd-glib/groovy/armhf

https://objectstorage.prodstack4-5.canonical.com/v1/AUTH_77e2ada1e7a84929a74ba3b87153c0ac/autopkgtest-groovy/groovy/armhf/s/snapd-glib/20210110_213607_6d4d0@/log.gz

...
Executing: snapd-glib/test-qt.test
Test timed out after 300 seconds
FAIL: snapd-glib/test-qt.test (Child process killed by signal 9)
Running test: snapd-glib/test-markdown-qt.test
# random seed: R02S8929c6fbcee911211dcbe25b8160bc06
1..13
# Start of markdown tests
...

Reproduction in Canonistack with lxd shows no sigificant difference in run time when testing with and without glibc from -proposed.

I assume the timeouts are results of the CI infrastructure running other tests in parallel on the same HW.