broken "fast" build - hung containers

[Ted Zlatanov]

I was cleaning the EMBA machines last night. Lots of hanging containers.
I think it was due to shm issues, but couldn't tell.

The "fast" EMBA build seems to be hanging. The normal one works. Seems
to be here:

https://emba.gnu.org/emacs/emacs/-/jobs/27726

  ELC      src/emacs-module-tests.elc
  GEN      src/emacs-module-tests.log
ERROR: Job failed: execution took longer than 3h0m0s second

I see two of them hanging right now (the docker containers have not been
removed). This probably is what started the cascade of failures that
broke EMBA.

I'll investigate when able, but if anyone has ideas, please let us know.

Ted