[Static Runtime] Added a variadic cat operator (#61302)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/61302
Test Plan: Imported from OSS
Reviewed By: hlu1
Differential Revision: D29565344
Pulled By: navahgar
fbshipit-source-id: 96f5f4546ec0e61eb7f87e016e026e7b62576248
