BTS_Tests: separate RACH / IMM ASS from f_est_dchan()

Given that the test suite acts as the BSC, it's known in advance
which exact logical channel is going to be activated.  Therefore,
it's not necessary to send an Immediate Assignment with the known
Channel Description IE over the Um interface (via L1CTL).

On the other hand, we may still want to validate the process of
dedicated channel establishment, involving the use of Immediate
Assignment procedure.  So instead of doing this every time when
a ConnHdlr component needs to activate a logical channel, let's
split the existing logic into a separate test case - TC_est_dchan.

This change facilitates the goal of running test cases against
additional transceivers (not only against C0).  Currently this
is not possible, because a ConnHdlr component has no access to
C0/AGCH when executed on Cx > 0.

Change-Id: I8df3db36f35190241735629a961f09d73bd0e5f5
1 file changed