Remove aten.elu core ATen decomp because it is now core ATen (#149780)

Per @larryliu0820.

Pull Request resolved: https://github.com/pytorch/pytorch/pull/149780
Approved by: https://github.com/larryliu0820

test/expect/HasDecompTest.test_aten_core_operators.expect

@@ -193,6 +193,8 @@ aten::div_.Scalar
 aten::div_.Scalar_mode
 aten::div_.Tensor
 aten::div_.Tensor_mode
+aten::elu
+aten::elu.out
 aten::embedding
 aten::embedding.out
 aten::empty_strided

test/export/test_export.py

@@ -13465,7 +13465,6 @@ class TestExportCustomClass(TorchTestCase):
         )
 
         decomp_table = default_decompositions()
-        del decomp_table[torch.ops.aten.elu.default]
 
         ep = ep.run_decompositions(
             decomp_table=decomp_table,

torch/_decomp/__init__.py

@@ -332,7 +332,6 @@ def _core_aten_decompositions_post_autograd() -> dict[
             aten.diagonal_copy,
             aten.dot,
             aten.vdot,
-            aten.elu,
             aten.elu_,
             aten.elu_backward,
             aten._embedding_bag,

torch/_inductor/decomposition.py

@@ -61,6 +61,7 @@ inductor_decompositions = get_decompositions(
         aten.bitwise_or_,
         aten.clamp_min_,
         aten.dist,
+        aten.elu,
         aten.empty_like,
         aten.flip,
         aten.gelu,