Add testsuite + scenarios to test nanoBTS multiTRX

Currently only 2 nanoBTS in the 900 band are attached together as a
multiTRX setup. We thus set num_trx to 2 and set channel allocator
descending to force the BTS to use the 2nd TRX when allocating channels.

Change-Id: I12e1bcb047c4efac5693cf725739e0ce2e0532ee
3 files changed