[primTorch] Strides for complex abs are incorrect

[mruberry]

a = torch.randn((2, 2)).transpose(0, 1)
a.stride()
: (1, 2)

result = torch.abs(a)
result.stride()
: (1, 2)

b = torch.randn((2, 2), dtype=torch.cfloat).transpose(0, 1)
b.stride()
: (1, 2)

result = torch.abs(b)
result.stride()
: (2, 1)

cc @ezyang @anjali411 @dylanbespalko @mruberry @lezcano @nikitaved @nairbv @ngimel

[mruberry]

I think this is happening because of

pytorch/aten/src/ATen/native/UnaryOps.cpp

Line 261 in 0f1618e

Tensor complex_result = at::empty({0}, self.options());

[ngimel]

Yep, this is wrong, but why abs (not out overload) even goes there? It should go to unary_op_impl_with_complex_to_float?