msan fixes for SBA, Stereo and MASA cases

EVS 26.444 BE test passes.
pytests results: 588 failed, 381 skipped

MLD scores:
Original inputs:
MLD > 10: 107; Out of these, 51 cases are PLC
MLD > 5 : 125
MLD < 5 : 366

+10dB inputs:
MLD > 10: 222
MLD > 5 : 190
MLD < 5 : 186

-10dB inputs:
MLD > 10: 72
MLD > 5 : 75
MLD < 5 : 451