BASOP asserts in MC 5.1 fx encoder for selection test inputs
# Basic info
- Git SHA: ecba0c5957e48af036b32b019ea3223da71ac624
# Bug description
Selection test inputs for 5.1 MC trigger asserts in the fixed-point encoder:
```
Frames processed: 255 Assertion failed: (0), function L_shl, file basop32.c, line 2582.
```
# Ways to reproduce
```
for bitrate in 13200 16400 24400 32000; do
./IVAS_cod_fx -mc 5_1 -max_band FB $bitrate 48 am2aa1s02_48.wav bit
done
```
issue