TC_tch_sign_l2_fill_frame_dtxd BTS_Tests:hopping

Failing for the past 692 builds since #2405

Took 2.1 sec (from Titan)

Stack Trace

Received DTX TCH fill frame with bad frame number: 175 (mod 104: 71) (mod 26: 19)
      BTS_Tests.ttcn:9573 BTS_Tests control part
      BTS_Tests.ttcn:8104 TC_tch_sign_l2_fill_frame_dtxd testcase