changing decomposition pattern

slice scatter changes

Review comments address

Removing arange and replacing with range

slice_scatter adding to decomposition group

using aten::scatter in aten.slice_scatter

Correcting the slice_scatter case with aten::scatter use

removing unnecessary cases from slice_scatter impl and adding test case

changing for loop to torch.arange

Reverting back the torch.arange to for loop

Adding test case for 3d cases and removing the casting to torch.int64 and including it torch.ones

Removing aten.index in the decomposition ops