Fix for issue 696: Audible "plop" at 16.4 kbps stereo likely due to ipd...

Fix for issue 696: Audible "plop" at 16.4 kbps stereo likely due to ipd difference between float and fixed point

EVS 26.444 BE test passes.
pytests results: 597 failed, 381 skipped

MLD scores:
Original inputs:
MLD > 10: 58
MLD > 5 : 120
MLD < 5 : 419

+10dB inputs:
MLD > 10: 186
MLD > 5 : 193
MLD < 5 : 218

-10dB inputs:
MLD > 10: 19
MLD > 5 : 59
MLD < 5 : 519