msc: add TC_mo_cc_bssmap_clear to catch OS#3062

The test currently crashes osmo-msc, which is fixed by
I5c30e0f9545fb76615776ff6cc16b56aeb5b043a (osmo-msc).

Related: OS#3062
Change-Id: Ic80646e1fba37bb6163ca3a7eead7980b4ad7a51
1 file changed