Index converter dynamic cases fix

[apbose]

This PR-

1. Addresses 🐛 [Bug] index and index_put don't support dynamic shapes #3647 for index
2. Adds a test case for dynamic index

[peri044]

The index dtype validator doesn't support bool type

(Pdb) node.args
(_reshape_copy_597, [eq_1427])
(Pdb) node.args
(_reshape_copy_597, [eq_1427])
(Pdb) node.args[0].dtype
*** AttributeError: 'Node' object has no attribute 'dtype'
(Pdb) node.args[0].meta['val']
FakeTensor(..., device='cuda:0', size=(s43*s53, 2048), dtype=torch.float16)
(Pdb) node.args[0].meta['val'].dtype
torch.float16
(Pdb) node.args[1][0].meta['val'].dtype
torch.bool

The inputs to index are FP16 and bool. In this case, converter is not being invoked and falls back to PyTorch

[apbose]

oh ok, looks like in https://github.com/zdevito/ATen/blob/master/aten/src/ATen/native/native_functions.yaml#L1324 tensor indices as bool should denote mask then. I think a non zero layer to get the corresponding indices should work. I will push in the change

[lanluo-nvidia]

One comment, please take a look, others LGTM

[apbose]

I think the tests are passing related to this test. @peri044 could you please review?