[DataLoader] ConcatDataPipe (#53301)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/53301
Test Plan: Imported from OSS
Reviewed By: anjali411
Differential Revision: D26829322
Pulled By: ejguan
fbshipit-source-id: eeea42fd9ab267d10f39ad7debc279eaded23570
