Float buffer/structure element cleanup and EVS/IVAS crash fixes

[x] Few float buffer cleanup
[x] ivas_td_binaural_renderer_sf converted to fixed point
[x] ivas_jbm_dec_flush_renderer intermediate conv cleanup
[x] Issue#728: Fixes crash issue due to incorrect scaling of shaped_shb_excitation_fx
[x] TonalMdctConceal_create_concealment_noise_ivas converted to fixed point.