[Non-BE] FIX_I102_SWB_TBE_SWITCH

Related to #102 (closed)

Fix for missing SWB TBE target signal after switch from TCX to ACELP. Affects 107 out of 212 conditions in self_test.prm. This is expected since it is in the core for low bitrate coding. The main listening effort was done for stereo@13.2 kbps 48 kHz input. Sample listening to the self_test cases did not reveal any issues.

@varga, @malenovsky, @multrus, review is welcome.