Use resultElementType for tensor creation for AtenMemoryFormatOp with none dtype.

[sahas3]

Prior to the change in this PR torch-mlir-opt --convert-torch-to-linalg was running into the following error:

error: 'tensor.cast' op operand type 'tensor<200x200x26xf32>' and result type 'tensor<200x200x26xf64>' are cast incompatible
    %1 = torch.aten.empty.memory_format %0, %none, %none, %none, %false, %none : !torch.list<int>, !torch.none, !torch.none, !torch.none, !torch.bool, !torch.none -> !torch.vtensor<[200,200,26],f64>
         ^
note: see current operation: %12 = "tensor.cast"(%11) : (tensor<200x200x26xf32>) -> tensor<200x200x26xf64

This is because when dtype of the aten.empty.memory_format is none, by default f32 was being selected as the element type of the resulting tensor which doesn't match with the actual element type of the result.

[sahas3]

Hi @ramiro050, I see that I am reverting your change here. It's not clear to me why the resultElementType was changed in that commit. I verified that the test you added passes with my change. Can you please take a look at this PR? Thanks!