Changes

testenv: get coredump + backtrace on crash

If the SUT or another test component crashes, check if a matching
coredump was registered in coredumpctl. If that is the case, then copy
it into the testdir and print + store the backtrace.

This solves the problem that it is especially tricky to get a good
backtrace when a component crashes inside a container. One needs to
grab the coredump from the host (usually handled by systemd-coredump,
we cannot override /proc/sys/kernel/core_pattern for containers so it
can't be handled in the container), then put the coredump into the
container and finally run gdb to get the backtrace inside the container
(where proper libraries and debug symbols are). This patch automates all
of these steps.

Pau requested this feature.

Related: OS#6494
Change-Id: I743c20968bda9b6d6fb9c2d23bef70ee11950761

library/s1ap: add E-RAB RELEASE templates

Change-Id: I2e9305da80934ea68e3eca8215a9c16de48b37fd

s1gw: derive functions from f_TC_e_rab_setup()

... to avoid code duplication when adding more E-RAB related TCs.

While at it, allow establishing multiple E-RABs.

Change-Id: I1bff371da6337ecd7710219d1c86f0fff82ad17f

s1gw: fix TC_e_rab_setup: handle PFCP Session related PDUs

S1GW_Tests.TC_e_rab_setup is failing since we introduced the PFCP
support to osmo-s1gw.  The IUT now requires co-located UPF, which
we need to emulate in the testsuite.

This patch patch adds the following API:

* S1GW_ConnHdlr.f_ConnHdlr_rx_session_establish_req(),
* S1GW_ConnHdlr.f_ConnHdlr_tx_session_establish_resp(),
* S1GW_ConnHdlr.f_ConnHdlr_rx_session_modify_req(),
* S1GW_ConnHdlr.f_ConnHdlr_tx_session_modify_resp(),

and makes use of it in S1GW_Tests.TC_e_rab_setup.

Change-Id: Ibbb326badaa1e3df968c137f3e4b576ca5c6f94d

s1gw: TC_e_rab_setup: also test E-RAB release

* s1ap: add E-RAB RELEASE API
* pfcp: add PFCP Session Deletion API
* s1gw: make use of this API in TC_e_rab_setup

Change-Id: Id995c51d8ac76316f41ef49d35380a2521d5ae19

s1gw: add TC_e_rab_setup3 (3 E-RABs at a time)

The idea is to verify setup and release of 3 E-RABs at a time.

Change-Id: I6a0a10f826309d8a952c77c23170df3d201e7640