PCU: Tests for the BSS/PCU side NS/BSSGP implementations

The existing (unused) PCU_Tests are operating on top of a NS + BSSGP
emulation, i.e. they're aimed at testing higher protocol layers.  Also,
they required BTS+BSC to run next to the PCU.

The new PCU_Tests_RAW introduced in this patch are the exact opposite:
* they test the PCU alone (attach to PCUIF and Gb interface)
* they don't require BTS or BSC to run
* they don't use NS + BSSGP emulation but raw NS/BSSGP frames to
  test the very NS/BSSGP implementation inside of OsmoPCU.

Change-Id: I7ad76b96974cf0a686ad0f00ccd09d1a9df8b4d5
Related: OS#2890
4 files changed