Support parsing Ellipsis in JIT frontend (#53576)
Summary:
De-sugars `Ellipsis` into dots (`...`)
Fixes https://github.com/pytorch/pytorch/issues/53517
Pull Request resolved: https://github.com/pytorch/pytorch/pull/53576
Reviewed By: pbelevich
Differential Revision: D26904361
Pulled By: gmagogsfm
fbshipit-source-id: 5b23e049a075a9a99e37dcb47a9410b6f82a6fb7
