add explicit paramter for infinite iterators

set appropriate value for num_epoch param for iteratos

fix long lines

remove trailing whitespace

fixed typo

remove comment

fixed comments

fixed test

This reverts commit b077aa1cab.

Revert "[feat] [assistant] [I3T96X] add new Dataset operator LibriSpeechDataset"

This reverts commit 4e6f7dc97d.

delete pass_registry_test.cc

comment  hiai_nlu_model_multi.pb related  line