Renderer cleanup changes, MSAN error fixes, MC reconfig cleanup

[x] Few MSAN errors for stereo fixed.
[x] renderMcToMasa(), renderInputMc(), renderActiveInputsMc() cleaned up
[x] MC dec config cleanup.

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

MLD scores:
Original inputs:
MLD > 10: 112; Out of these, 51 cases are PLC
MLD > 5 : 116
MLD < 5 : 360

+10dB inputs:
MLD > 10: 306
MLD > 5 : 119
MLD < 5 : 163

-10dB inputs:
MLD > 10: 72
MLD > 5 : 65
MLD < 5 : 450