Changes

ttcn3-bts-test/jenkins.sh: tweak local vars

Make it consistent.

Change-Id: I8c5597f20428f8f274ea15f62e561562e5768460

ttcn3-bts-test: run bpftrace scripts

Add logic to run bpftrace scripts attached to osmo-bts-* while the
testsuite runs. The initial script is from Vadim:
https://gitea.osmocom.org/osmocom/bpftrace-scripts/src/branch/master/udp_sendmsg_delay.bt

Change-Id: I5c22cdbb08fe797be936ca174f65ade626fa4895

common/respawn: improve logging

Add "[$(date)] respawn:" infront of all log messages, so it is clear
that they come from this script and so we have timestamps that we can
compare. This will be useful when running the bpftrace scripts along
with osmo-bts-*, which will get restarted at the same time as the
osmo-bts-* processes.

Change-Id: I641f17f6988eced12c9b301042fb5c5cfd757511

ttcn3-bts-test: give bpftrace time to print stats

When running with bpftrace, send a kill signal to the bpftrace scripts
before killing the container. Otherwise the scripts don't print their
statistics, the end of the log then looks like this:

  [Thu Dec 18 18:06:06 UTC 2025] respawn: 2: starting: /data/bpftrace/udp_sendmsg_delay.sh
  + pidof osmo-bts-trx
  + bpftrace /data/bpftrace/udp_sendmsg_delay.bt -p 56
  Attaching 3 probes...
  Tracing udp_sendmsg() latency... Hit Ctrl-C to end.

Change-Id: I1781bddddf429c4c6a951b519a639b8663d397e6

ttcn3-bts-test: mount tracingfs only when needed

Change-Id: I59bbbc96c0686a2c8792626297e656df72e578ed