Encoder crash for P.800 ACR-1 Stereo in swb_tbe_enc_ivas_fx()

Basic info

• Fixed point:
  • Encoder (fixed): 20250826_branch_release_characterization_testing_main @ b04e6d98

Bug description

While attempting to encode the concatenated file for c27, an assert is hit:

Assertion failed: (0), function shl, file basop32.c, line 792.

Saturation in frame 2243, occurs here:

/* this is needed as the E_LPC_lev_dur function outputs lpc in Q14 */
scale_sig( lpc_shb_fx, LPC_SHB_ORDER + 1, sub( norm_s( lpc_shb_fx[0] ), 2 ) );

• BASOP: lpc_shb_fx[] = {2048, 6341, 12023, 17060, 19269, 17726, 13272, 7934, 3592, 1087, 153}
• Float: lpc_shb[] = {1, 1.18623614, 0.610721946, 0, 0, 0, 0, 0, 0, 0, 0}

Ways to reproduce

Box folder: ...\Box_EXTERNAL_IVAS_CHAR_MC\Issues\basop-issue-2004

./IVAS_cod_fx -max_band SWB -q -stereo 24400 32 20ms_aligned_files_concatenated.cod_fmt.wav  bit