[Static Runtime] Add native op support for `aten::len` (#73899)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/73899
This change adds native op wrappers to Static Runtime as appears in JIT (https://www.internalfb.com/code/fbsource/[429d233b9beb5e6f60df7304b792e2ff332f6ecd]/fbcode/caffe2/torch/csrc/jit/runtime/register_prim_ops.cpp?lines=613 , search for "aten::len" in that file).
Test Plan: Added unittests, "StaticRuntime.LenWith*", and confirmed they are passing with `V0307 17:39:39.817956 3516654 impl.cpp:1792] Switch to native impl for node: %2 : int = aten::len(%input.1)` per added unittest: P485159811
Reviewed By: mikeiovine
Differential Revision: D34705231
fbshipit-source-id: 916b1f8bdbc92def07bc3f98ce1db22f0f5ce206
(cherry picked from commit 66d2bb9a0a294b55e1bc87ae33f5553b1460e74b)
