Assert (Overflow) in ivas_compute_core_buffers_fx()
# Bug description
Seems that !2976 has introduced asserts in a few LTV cases:
```
#4 0x00007ffff7cd3420 in __assert_fail_base (fmt=<optimized out>, assertion=<optimized out>, file=<optimized out>, line=792, function=<optimized out>) at ./assert/assert.c:118
#5 0x0000555555930f54 in shl (var1=10, var2=12) at lib_basop/basop32.c:792
#6 0x000055555571b6f2 in ivas_compute_core_buffers_fx (st=0x555555a580b0, inp16k_out_fx=0x7ffffffdb4e8, old_inp_16k_fx=0x7ffffffe6d40, new_inp_resamp16k_out_fx=0x7ffffffddde0, input_frame=960, last_element_mode=2, sr_core=16000, ener_fx=0x7ffffffe6534,
A_fx=0x7ffffffe63d0, Aw_fx=0x7ffffffe6270, epsP_fx=0x7ffffffe61e0, lsp_new_fx=0x7ffffffe6190, lsp_mid_fx=0x7ffffffe6150, Q_old_inp_16k=11, Q_r=0x7ffffffdb4e4, Q_new=0x7ffffffdb4e2) at lib_enc/ivas_core_pre_proc_fx.c:1211
#7 0x0000555555719161 in pre_proc_ivas_fx (st=0x555555a580b0, last_element_mode=2, element_brate=18800, last_element_brate=18800, input_frame=960, old_inp_12k8_fx=0x7ffffffe9680, old_inp_16k_fx=0x7ffffffe6d40, inp_fx=0x7ffffffde2e0, ener_fx=0x7ffffffe6534,
A_fx=0x7ffffffe63d0, Aw_fx=0x7ffffffe6270, epsP_fx=0x7ffffffe61e0, epsP_fx_q=0x7ffffffe61dc, lsp_new_fx=0x7ffffffe6190, lsp_mid_fx=0x7ffffffe6150, new_inp_resamp16k_fx=0x7ffffffddde0, q_new_inp_resamp16k_fx=0x7ffffffddddc, Voicing_flag=0x7ffffffdb99c,
old_wsp_fx=0x7ffffffde5a0, e_old_wsp=7, loc_harm=0, vad_flag_dtx=1, MCT_flag=0, vad_hover_flag=0, flag_16k_smc=0, enerBuffer_fx=0x7ffffffe2320, e_enerBuffer=5, fft_buff_fx=0x7ffffffe6540, cor_map_sum_fx=0, Q_new=0x7ffffffde596) at lib_enc/ivas_core_pre_proc_fx.c:629
#8 0x000055555570f840 in ivas_core_enc_fx (hSCE=0x0, hCPE=0x555555a575e0, hMCT=0x0, n_CoreChannels=1, old_inp_12k8_fx=0x7ffffffe9680, old_inp_16k_fx=0x7ffffffe6d40, Q_new=0x7ffffffde596, ener_fx=0x7ffffffe6534, A_fx=0x7ffffffe63d0, Aw_fx=0x7ffffffe6270,
epsP_fx=0x7ffffffe61e0, epsP_fx_q=0x7ffffffe61dc, lsp_new_fx=0x7ffffffe6190, lsp_mid_fx=0x7ffffffe6150, vad_hover_flag=0x7ffffffe614c, attack_flag=0x7ffffffe6148, realBuffer_fx=0x7ffffffe4340, imagBuffer_fx=0x7ffffffe2540, q_re_im_buf=0x7ffffffe253c,
old_wsp_fx=0x7ffffffde5a0, e_old_wsp=0x7ffffffde59c, loc_harm=0x7ffffffe250c, cor_map_sum_fx=0x7ffffffe2508, vad_flag_dtx=0x7ffffffe2504, enerBuffer_fx=0x7ffffffe2320, enerBuffer_fx_exp=0x7ffffffe231c, fft_buff_fx=0x7ffffffe6540, tdm_SM_or_LRTD_Pri=0,
ivas_format=7, flag_16k_smc=0) at lib_enc/ivas_core_enc_fx.c:242
#9 0x0000555555725d8e in ivas_cpe_enc_fx (st_ivas=0x555555a0b2d0, cpe_id=0, data_fx_ch0=0x555555a0dd30, data_fx_ch1=0x555555a0ec40, q_data_fx=12, input_frame=960, nb_bits_metadata=34, Q_new_out=0x0) at lib_enc/ivas_cpe_enc_fx.c:1388
#10 0x000055555558d766 in ivas_enc_fx (st_ivas=0x555555a0b2d0, data=0x555555a878e0, n_samples=4800) at lib_enc/ivas_enc_fx.c:435
#11 0x0000555555560f56 in IVAS_ENC_EncodeFrameToSerial (hIvasEnc=0x555555a0b2a0, inputBuffer=0x555555a878e0, inputBufferSize=4800, outputBitStream=0x7ffffffeb0b0, numOutBits=0x7ffffffeb0ae) at lib_enc/lib_enc_fx.c:1533
#12 0x000055555555b49e in main (argc=13, argv=0x7fffffffe158) at apps/encoder.c:926
```
This happens in frame 4047 for the commandline below.
The problem disappears once `NONBE_FIX_ISSUE_2518` gets disabled.
# Ways to reproduce
<!--Commandline or script-->
```bash
IVAS_cod -q -ism_masa 3 2 ltv48_OMASA_3ISM_2TC_ISM1.csv ltv48_OMASA_3ISM_2TC_ISM2.csv ltv48_OMASA_3ISM_2TC_ISM3.csv ltv48_OMASA_3ISM_2TC.met ivas-codec/scripts/switchPaths/sw_13k2_512k_2fr_start_160k_omasatechs_3ism.bin 48 ltv48_OMASA_3ISM_2TC.wav out.wav
```
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issue