[JIT] Add dynamic shape benchmark for NV Fuser (#46107)
Summary:
This PR modifies `benchmarks/tensorexpr`. It follows up[ https://github.com/pytorch/pytorch/issues/44101](https://github.com/pytorch/pytorch/pull/44101) and further supports characterizing fusers with dynamic shape benchmarks. Dynamic shape condition models the use case when the input tensor shape changes in each call to the graph.
Changes include:
Added an auxiliary class `DynamicShape `that provides a simple API for enabling dynamic shapes in existing test cases, example can be found with `DynamicSimpleElementBench`
Created new bench_cls: `DynamicSimpleElementBench`, `DynamicReduce2DInnerBench`, `DynamicReduce2DOuterBench`, and `DynamicLSTM`. They are all dynamic shaped versions of existing benchmarks and examples of enabling dynamic shape with `DynamicShape`.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/46107
Reviewed By: glaringlee
Differential Revision: D24229400
Pulled By: bertmaher
fbshipit-source-id: 889fece5ea87d0f6f6374d31dbe11b1cd1380683
