CoreML randn_like fails to lower with internal error

[GregoryComer]

🐛 Describe the bug

Models with torch.randn_like fail to lower with an internal error in coremltools.

Repro:

import torch

from executorch.backends.apple.coreml.partition import CoreMLPartitioner
from executorch.exir import to_edge_transform_and_lower, EdgeCompileConfig, to_edge
from executorch.extension.pybindings.portable_lib import _load_for_executorch_from_buffer

class Model(torch.nn.Module):
    def __init__(self):
        super().__init__()
        
    def forward(self, x):
        return torch.randn_like(x)

model = Model()
inputs = (
    torch.zeros(5, 5),
)

print(inputs)

eager_outputs = model(*inputs)
print(f"Eager: {eager_outputs.shape} {eager_outputs}")

ep = torch.export.export(model.eval(), inputs)
print(ep)

print(f"EP: {ep.module()(*inputs)}")

lowered = to_edge_transform_and_lower(
    ep,
    partitioner=[CoreMLPartitioner()],
    compile_config=EdgeCompileConfig(_check_ir_validity=False)
).to_executorch()

print(lowered.exported_program())

et_model = _load_for_executorch_from_buffer(lowered.buffer)
et_outputs = et_model([*inputs])[0]

print(et_outputs)

et_outputs - eager_outputs

Output:

File [~/miniconda3/envs/executorch/lib/python3.10/site-packages/coremltools/converters/mil/frontend/torch/ops.py:274](http://localhost:8888/lab/tree/~/miniconda3/envs/executorch/lib/python3.10/site-packages/coremltools/converters/mil/frontend/torch/ops.py#line=273), in _get_inputs.<locals>.check_if_number_of_inputs_expected(num_inputs, expected)
    272 expected = [expected] if isinstance(expected, int) else expected
    273 if num_inputs not in expected:
--> 274     raise ValueError(
    275         f"node {node.name} ({node.kind}) got {num_inputs} input(s), expected {expected}"
    276     )

ValueError: node aten_randn_like_default (randn_like) got 1 input(s), expected [6]

Versions

coremltools version 8.3
executorch commit 67b6009 (Jun 14)

cc @kimishpatel @YifanShenSZ @cymbalrush @metascroy