BSC_Tests: Don't make invalid assumptions about RR RELEASE

The RR RELEASE message does not always have to be '060D00'O,
which constrains it to:
* not having any optional IEs
* not having a cause value != 00

Let's relax the matching to accept any RR RELEASE message, whatever
the cause may be, and whether or not there are any optional IEs at the
end.

At the same time, also remove some copy+pasting but rather have one
template that gets used everywhere.

Change-Id: I4b9d078c9b66f040fe673b5d957cf8e2c6d5892c
2 files changed