Arm backend: Fix bug in ConvertExpandCopyToRepeatPass

In the ConvertExpandCopyToRepeatPass the arguments for the repeat operation are formed incorrectly.
For the torch.Tensor.expand operation passing -1 as the size for a dimension means that the size of that dimension does not change.
For the DeiT-tiny case, torch.ones(1, 1, 192).expand(1, -1, -1) the pass will prepare arguments to the repeat operation as [1, -1, 1] which will cause an error, in this case the arguments should be [1, 1, 1].