Draft: Resolve "Harmonize perform_noise_estimation_enc_(ivas)fx" + minimum_statistics(fx_) + expand_range_(fx_)

copy from issue #2485:

The functions perform_noise_estimation_enc_fx and perform_noise_estimation_enc_ivas_fx can be harmonized quite easily.

In a second step, the callees minimum_statics() and minimum_statistics_fx() , as well as expand_range() and expand_range_fx() can be harmonized, too