handover_test: show a bug: add test_congestion_no_oscillation.ho_vty

Also add test_congestion_no_oscillation2.ho_vty which is an almost
identical scenario that does not show the bug -- because it has two more
TCH/H available in BTS 1, showing the strange behavior of the algorithm.

Related: SYS#5259
Change-Id: Idf88b4cf3d2f92f5560d73dae9e59af39d0494c0
3 files changed