Travis builds are hanging mid-print

Filing this since it keeps happening. PR #4119 was my attempt to diagnose it.

The cross-compile job (the 3rd job) has been repeatedly failing ever since PR #4118 except in the diagnostic attempt. It looks like this:

663$ suite/runsuite_wrapper.pl travis $EXTRA_ARGS
664
665
666No output has been received in the last 10m0s, this potentially indicates a stalled build or something wrong with the build itself.
667Check the details on how to adjust your build configuration on: https://docs.travis-ci.com/user/common-build-problems/#build-times-out-because-no-output-was-received
668
669The build has been terminated
670

Very strange.