Changes

jobs/osmo-gsm-tester-runner: use debian bookworm

* Use bookworm during clean up instead of bullseye
* Don't build debian-buster-jenkins anymore, the osmo-gsm-tester
  container now uses debian-bookworm-build which gets deployed via the
  update-osmo-ci-on-slaves job (see commit in Depends:)

Related: OS#6126
Depends: docker-playground I5ed3b92f07f23c96b8f953e0a93991cc89476a12
Change-Id: I065acebbcb11fbddc5a65f5c12baab0461c50b66

jobs/osmo-gsm-tester-builder: build in docker

Build Osmocom programs in docker (debian bookworm), so they link
against libraries available when trying to run the programs later on.

Without this we get errors like to following when
osmo-gsm-tester-virtual runs in docker with debian bookworm (after
recent change, before that it used debian buster):
  osmo-msc: error while loading shared libraries: libasan.so.5: cannot open shared object file: No such file or directory

Fixes: OS#6126
Change-Id: I109132fbb7b459652efafad4484c3fc01293bd3f

jobs: Move ttcn3-stp-test* to use testenv

Depends: osmo-ttcn3-hacks.git e85c0c3069f03068d7187bf971a3e4139f5c4bd0
Change-Id: Ifdee05395c4c80a3c9cb60828c268bcbb8f430a8