adding select_scatter decomp

Author: apbose

py/torch_tensorrt/dynamo/lowering/_decomposition_groups.py

@@ -174,6 +174,7 @@
     aten.full,
     aten.repeat,
     aten.var_mean,
+    aten.select_scatter,
 }
 torch_disabled_decompositions: Set[Union[OpOverload, OpOverloadPacket]] = {
     aten._softmax.default,

tests/py/dynamo/lowering/test_decompositions.py

@@ -434,6 +434,7 @@ def forward(self, x, src, dim, index):
             torch.ops.aten.slice.Tensor,
             torch.ops.aten.squeeze.dim,
             torch.ops.aten.cat.default,
+            torch.ops.aten.reshape.default,
         }
         unexpected_ops = {torch.ops.aten.select_scatter.default}
 
@@ -496,6 +497,7 @@ def forward(self, x, src, dim, index):
         expected_ops = {
             torch.ops.aten.slice.Tensor,
             torch.ops.aten.squeeze.dim,
+            torch.ops.aten.unsqueeze.default,
             torch.ops.aten.cat.default,
         }
         unexpected_ops = {torch.ops.aten.select_scatter.default}