Unexpected removal of copy operations in nvfuser executor's fusion pass

@beverlylytle is already working on this.

Since Mar 26, 2025.

When `update_aliases' is [supported](https://github.com/Lightning-AI/lightning-thunder/blob/71f89ab49288fcd54f65bd4633aac72dd72560ad/thunder/executors/nvfuserex_impl.py#L1734) in the nvfuser executor, [setting an item on a view fails](https://github.com/Lightning-AI/lightning-thunder/blob/71f89ab49288fcd54f65bd4633aac72dd72560ad/thunder/tests/test_update_aliases.py#L38) in an unexpected way. In the fusion pass on the first function in the above-mentioned test, the following 5 bound_symbol_groups are created:
```
[# x: "cuda:0 f32[2, 3]"],
[(t5,) = prims.update_aliases((x,)), y = ltorch.view(t5, (3, 2)) # y: "cuda:0 f32[3, 2]"
# y = ltorch.reshape(t5, (3, 2)) # y: "cuda:0 f32[3, 2]"
# y = prims.reshape(t5, (3, 2)) # y: "cuda:0 f32[3, 2]", (t6, t7) = prims.update_aliases((y, t5)), t2 = ltorch.getitem(t6, 0) # t2: "cuda:0 f32[2]"
# t1 = prims.slice_prim(t6, [0, 0], [1, 2], [1, 1]) # t1: "cuda:0 f32[1, 2]"
# t2 = prims.squeeze(t1, (0,)) # t2: "cuda:0 f32[2]", (_, t9, t10) = prims.update_aliases((t6, t7, t2))],
[t12 = copy_with_setitem_impl(t10, 0, 0) # t12: "cuda:0 f32[2]"],
[prims.copy_(t12, t10, grad_enabled=True)],
[return {'output': (t9,), 'flat_args': [t9]}]
```
The second to last bsym has no output, and it DCE'd away, the third to last bsym's output is not used, and so is DCE'd away. Thus, no item assignment occurs.