[xnnpack][lite-int][graph-build] graph passes and op checking (#87128)
Beginning of building the xnnpack graph from the torchscript IR. We first massage the torchscript graph using a few graph passes that perform things such as unused self argument removal and constant propagation.
This also performs tracing for us so that the model does not have to be prepped by tracing before being lowered by us.
The other check we perform is through the torchscript IR to identify any nodes that are not lowerable/supported, and throwing an error to spit out the specific nodes that are not lowerable.
Differential Revision: [D39838338](https://our.internmc.facebook.com/intern/diff/D39838338/)
**NOTE FOR REVIEWERS**: This PR has internal Meta-specific changes or comments, please review them on [Phabricator](https://our.internmc.facebook.com/intern/diff/D39838338/)!
Pull Request resolved: https://github.com/pytorch/pytorch/pull/87128
Approved by: https://github.com/salilsdesai
