Fix zero size tensors (#3702)

Summary:
Pull Request resolved: https://github.com/pytorch/executorch/pull/3702

## Context

Dispatching a command buffer with a work group size that contains 0 is undefined behaviour. On some devices, this can cause the device to be lost. Fix this by setting the work group size to `{1, 1, 1}` right before dispatching a command buffer if the work group size contains a 0.

Reviewed By: yipjustin

Differential Revision: D57655257

fbshipit-source-id: 6209668c960f0e0afb0de0ab8b09c285e2de56b9