Add sizes to TransformEosLangPairDataset
Add sizes to TransformEosLangPairDataset

Summary: LangPairDataset was updated with sizes to improve efficiency, so also added it to TransformEosLangPairDataset.

Reviewed By: pipibjc

Differential Revision: D23817426

fbshipit-source-id: d62a4ac3535a06618ff70c717ab55f43fc6d48c6

pytorch/fairseq,pytorch/fairseq,pytorch/fairseq