So far we do all channel reassignments by Handover Command. Since
osmo-bsc now supports rassignment of ongoing voice calls, do intra-cell
congestion resolution by Assignment Command.
In effect, add support for expecting an Assignment Command in
handover_test, and expect assignments instead of handovers for
intra-cell congestion resolution test cases.
Related: SYS#5330 OS#3277
Change-Id: Id56a890106b93fcee67ac9401b890e7b63bba421
Name both new tests with suffix '_2' even though the first h_to_f does
not exist (yet?), to indicate the complementary nature of those two
tests.
Related: SYS#5301
Change-Id: I8c8d9d5936f713f7d02e4246eeb373916e62510b