Update checkpointing to support model parallel
This pull request **introduces 1 alert** when merging f0345ed4dbf94798b1375f4798b997ebd1115f22 into 99ed9c2ae5c840a8723f236530ccb1abe8c75377 - [view on LGTM.com](https://lgtm.com/projects/g/NVIDIA/NeMo/rev/pr-fa795c7f3253cb10f0b090983cf620dbc7125e51)

**new alerts:**

* 1 for Unused import This pull request **introduces 1 alert** when merging d7da994dbae189c1e02a6f51efe924046ca2f03b into 99ed9c2ae5c840a8723f236530ccb1abe8c75377 - [view on LGTM.com](https://lgtm.com/projects/g/NVIDIA/NeMo/rev/pr-9bea83783937cb7e953f7b8a603b137f54e21238)

**new alerts:**

* 1 for Unused import This pull request **fixes 2 alerts** when merging 0e0f7cfcf8579705f3e7dad5d6f54340e0ecb8f0 into 4de7bd8394fb7e809e04ee8bcadcf9a1711ef497 - [view on LGTM.com](https://lgtm.com/projects/g/NVIDIA/NeMo/rev/pr-8aa805f1579286cee43cd4b310d05532f97d9e0b)

**fixed alerts:**

* 2 for Unused local variable
TODO