add eq.str op to lite interpreter (#38859)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/38859
This error message indicates aten::eq expects different types
```
RUNNING 379 OP 76, aten::eq
terminate called after throwing an instance of 'c10::Error'
what(): isInt() INTERNAL ASSERT FAILED at "buck-out/gen/68e83026/xplat/caffe2/aten_header#header-mode-symlink-tree-with-header-map,headers/ATen/core/ivalue.h":331, please report a bug to PyTorch.
```
It turns out that there are two aten::eq in lite interpreter (https://www.internalfb.com/intern/diffusion/FBS/browse/master/xplat/caffe2/torch/csrc/jit/runtime/register_prim_ops.cpp?lines=417)
aten::eq(int, int)
aten::eq(str, str)
This diff add overload name for str and it fixed the problem.
Test Plan: local test
Reviewed By: pengtxiafb
Differential Revision: D21681838
fbshipit-source-id: 1f17ecdadb9bc1c16915a24c60fa57a6fc273865
