Resolve "Saturation possible for 32kbps stereo PLC"

Closes #683 (closed)

pytest results: 358 failed, 227 passed, 381 skipped

MLD:
Original: 7 cases > 5
8.622665 9.193538 10.831529 10.852825 12.475984 20.908897 22.46314

+10dB: 23 cases > 5
5.663041 5.663041 6.289222 6.327793 6.992729 7.061021 7.341063 7.782791 7.858091 10.755767 10.755767 11.334802 14.462528 15.20342 16.607782 16.9758 17.577244 19.321316 19.374035 19.76078 23.576723 27.352047 38.927044

-10dB: 8 cases > 5
5.726532 5.964953 6.009441 6.918595 7.063228 8.736409 14.835657 15.85611