ns for fx: make layer types more readable (#64270)

ns for fx: make layer types more readable (#64270)

Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/64270

Before this PR, layer types were populated by doing
`str(module_instance)` and `str(function)`. This resulted
in moderately readable strings for modules, and poorly readable
strings for functions.

This PR switches the logic to use `torch.typename` utility instead.
The results are significantly more readable.

Example function type:

```
# before
'<built-in method linear of PyCapsule object at 0x7fe9b20ce7b0>'

# after
'torch._ops.quantized.PyCapsule.linear'
```

Example module type:

```
# before
"<class 'torch.nn.quantized.modules.conv.Conv2d'>"

# after
'torch.nn.quantized.modules.conv.Conv2d'
```

Test Plan:
Manually inspect NS results for modules and functions, verify they are
more readable.

Manually inspect NS results for modules and functions, verify they are
more readable.

Imported from OSS

Differential Revision:
D30669545
D30669545

Reviewed By: jerryzh168

Pulled By: vkuzo

fbshipit-source-id: 60959e5cafa0a4992b083bf99f5d8260f9acdac0