[static runtime] Move all heavy constructor logic into InferenceModule (renamed to StaticModule) (#51564)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/51564
Constructor logic was spread throughout InferenceModule and StaticRuntime. This diff unifies the two. After a lot of discussion on this diff D25961626 it became apparent that `clone` is uglier than a cheap StaticRuntime.
This means StaticRuntime is effectively StaticModule and the only code in the new StaticRuntime is the `run` functions.
```
graph, schema = PrepareForStaticModule(torchscript_module)
sm = StaticModule(graph, schema, options)
sm(inputs)
// or create many cheap runtimes with the module
sr = StaticRuntime(sm)
sr(inputs)
```
Changelist:
- Rename InferenceModule StaticModule
- Move all logic for construction into StaticModule
- Create a new StaticRuntime that only has a unique memory planner (everything else is in StaticModule)
- Update comments with explanation
- Propagate all changes to predictor integration
- Propagate all changes to python integration
- Change semantics to be a bit more PyTorch-standard (no "run" calls, no "get_" getters).
Test Plan:
buck test //caffe2/test:static_runtime
buck test caffe2/benchmarks/static_runtime:static_runtime_cpptest
Reviewed By: hlu1
Differential Revision: D25592967
fbshipit-source-id: 8233bed03137ce129137af2d44bce0095033ef0f
