gather of setindex scatter

```
%221 = "stablehlo.scatter"(%c_48, %c_42, %52) <{indices_are_sorted = false, scatter_dimension_numbers = #stablehlo.scatter, unique_indices = true}> ({
^bb0(%arg17: tensor, %arg18: tensor):
stablehlo.return %arg18 : tensor
}) : (tensor<5xui32>, tensor<4x1xi32>, tensor<4xui32>) -> tensor<5xui32>
%222 = "stablehlo.gather"(%221, %c_42) <{dimension_numbers = #stablehlo.gather, indices_are_sorted = false, slice_sizes = array}> : (tensor<5xui32>, tensor<4x1xi32>) -> tensor<4xui32>
```

source jaxmd

Begin by reproducing the StableHLO scatter followed by gather shown in the issue, using the supplied JAX source as the entry point. Compare the generated IR with the intended behavior, but note that no file, test, failure description, or acceptance criterion is provided, so the completion condition needs clarification.

Written by the indexing model from the issue text.