[Static Runtime] Test isOptimizableContainerType and getAlwaysAliveValues (#65849)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/65849
Add tests for some of `StaticModule`'s exposed methods. Both of these are used by the memory planner, so it would be helpful to have some unit tests that ensure our basic invariants don't break.
Test Plan: `buck test caffe2/benchmarks/static_runtime:static_runtime_cpptest`
Reviewed By: hlu1
Differential Revision: D31282901
fbshipit-source-id: e390329f4794e034170507e3a0de0abcfe0ab7b9
