Enable fsanitize-unsigned-integer for G711 soft decoder.

Enable fsanitize-unsigned-integer for the G711 soft decoder
and refactor the while loops in DecodeALaw and DecodeMLaw
to not trigger the sanitizer upon completion.

Bug: 23110888
Change-Id: I473b430279ab21e9e7c4f854cdae449a53ad82bc
2 files changed