Overlong IMSIs used to trigger an assertion failure in osmo-msc.
This problem has been fixed but there was no test for it yet.
A lazy way of testing for this problem is to send an overlong IMSI
from an existing test which already verifies related behaviour
and would fail if the MSC crashed: TC_lu_by_tmsi_noauth_unknown
However, osmo-msc currently accepts overlong IMSIs and silently
truncates them, so this change as-is currently breaks this test.
But I would argue that osmo-msc's current behaviour is unreasonable
anyway and have proposed a patch to change it:
https://gerrit.osmocom.org/#/c/osmo-msc/+/9739/
With that patch applied to osmo-msc, this test keeps passing.
Change-Id: I2c472bee76086f6c84ec684d2e58b3351ebc3147
Depends: I785c994f41a646d8d83d3d82f5a9ae6b572eb641
Related: OS#2864
Related: g#9739
04fc4bcc18