Isolate src code and testing for DeepSpeed-FastGen (#4610)
Co-authored-by: Jeff Rasley <jerasley@microsoft.com>
Co-authored-by: Michael Wyatt <michaelwyatt@microsoft.com>
Co-authored-by: Ammar Ahmad Awan <ammar.awan@microsoft.com>
Co-authored-by: Masahiro Tanaka <mtanaka@microsoft.com>
Co-authored-by: Logan Adams <114770087+loadams@users.noreply.github.com>
