SBA decoder crashed on LTV test vectors

Commit sha: 31560a87

I ran SBA pytests with long test vectors. It revealed 16 crashes. 4 of them crahsed in basop32.c:507, 4 of them at basop32.c:2582, and 8 of them at basop32.c:834. Following are command lines to reproduce some of the crashes.

crashing at 507:

./IVAS_dec -q -fr 20 FOA 48 ltv48_FOA_ivasbr32k_DTX1_Gain0_dutenc.192.PLperc40mblen50.g192.fer ltv48_FOA_ivasbr32k_DTX1_Gain0_PLperc40mblen50.wav

crashing at 2582:

./IVAS_dec -q -fr 20 FOA 32 ltv32_FOA_ivasbr32k_DTX1_Gain0_dutenc.192.PLperc40mblen50.g192.fer ltv32_FOA_ivasbr32k_DTX1_Gain0_PLperc40mblen50.wav

crashing at 834

./IVAS_dec -q -fr 20 FOA 48 ltv48_FOA_ivasbr64k_DTX0_Gain0_dutenc.192.PLperc40mblen50.g192 ltv48_FOA_ivasbr64k_DTX0_Gain0_PLperc40mblen50.wav