MC encoder crashing with bitrate and bandwidth switching

See #943 (closed). There is a problem with the IGF reconfiguration with bitrate and bandwidth switching.

Reproduce with:

./IVAS_cod -mc 5_1 -max_band scripts/testv/ivas_bws_20fr_start_WB.txt /Users/knj/Documents/IVAS/PC/ivas-codec/scripts/switchPaths/sw_24k4_256k.bin 48 scripts/testv/stv51MC48c.wav bit

results in

fish: Job 1, '/Users/knj/Documents/IVAS/PC/iv…' terminated by signal SIGSEGV (Address boundary error)