Torch export can't support dynamics shapes for lstm

[ZORO-Q]

🐛 Describe the bug

class Basic(torch.nn.Module):
    def __init__(self):
        super().__init__()
        self.lstm = nn.LSTM(320,64,num_layers=1, bidirectional=False, batch_first=True)

    def forward(self, x: torch.Tensor) -> torch.Tensor:
        x, _  = self.lstm(x)
        return x


example_args = (torch.randn(1,100,320),)
dim1_x = Dim("dim1_x", min=6, max=100000)
dynamic_shapes = {"x": {1: dim1_x}}
aten_dialect: ExportedProgram = export(
    Basic(), example_args, dynamic_shapes=dynamic_shapes
)
print(aten_dialect)

Traceback (most recent call last):
  File "<string>", line 14, in <module>
  File "/home/yaqiong.he/.conda/envs/executorch/lib/python3.10/site-packages/torch/export/__init__.py", line 174, in export
    return _export(
  File "/home/yaqiong.he/.conda/envs/executorch/lib/python3.10/site-packages/torch/export/_trace.py", line 945, in wrapper
    raise e
  File "/home/yaqiong.he/.conda/envs/executorch/lib/python3.10/site-packages/torch/export/_trace.py", line 928, in wrapper
    ep = fn(*args, **kwargs)
  File "/home/yaqiong.he/.conda/envs/executorch/lib/python3.10/site-packages/torch/export/exported_program.py", line 89, in wrapper
    return fn(*args, **kwargs)
  File "/home/yaqiong.he/.conda/envs/executorch/lib/python3.10/site-packages/torch/export/_trace.py", line 1455, in _export
    aten_export_artifact = export_func(
  File "/home/yaqiong.he/.conda/envs/executorch/lib/python3.10/site-packages/torch/export/_trace.py", line 1060, in _strict_export
    gm_torch_level = _export_to_torch_ir(
  File "/home/yaqiong.he/.conda/envs/executorch/lib/python3.10/site-packages/torch/export/_trace.py", line 529, in _export_to_torch_ir
    raise UserError(UserErrorType.CONSTRAINT_VIOLATION, str(e))  # noqa: B904
torch._dynamo.exc.UserError: Constraints violated (dim1_x)! For more information, run with TORCH_LOGS="+dynamic".
  - Not all values of dim1_x = L['x'].size()[1] in the specified range 6 <= dim1_x <= 100000 are valid because dim1_x was inferred to be a constant (100).

Suggested fixes:
  dim1_x = 100```

### Versions

PyTorch version: 2.5.0.dev20240901
Is debug build: False
CUDA used to build PyTorch: None
ROCM used to build PyTorch: N/A

OS: macOS 14.5 (arm64)
GCC version: Could not collect
Clang version: 15.0.0 (clang-1500.3.9.4)
CMake version: version 3.29.6
Libc version: N/A

Python version: 3.10.0 (default, Mar 3 2022, 03:54:28) [Clang 12.0.0 ] (64-bit runtime)
Python platform: macOS-14.5-arm64-arm-64bit
Is CUDA available: False
CUDA runtime version: No CUDA
CUDA_MODULE_LOADING set to: N/A
GPU models and configuration: No CUDA
Nvidia driver version: No CUDA
cuDNN version: No CUDA
HIP runtime version: N/A
MIOpen runtime version: N/A
Is XNNPACK available: True

CPU:
Apple M3

Versions of relevant libraries:
[pip3] executorch==0.4.0a0+99fbca3
[pip3] numpy==1.21.3
[pip3] torch==2.5.0.dev20240901
[pip3] torchaudio==2.5.0.dev20240901
[pip3] torchsr==1.0.4
[pip3] torchvision==0.20.0.dev20240901
[conda] executorch 0.4.0a0+99fbca3 pypi_0 pypi
[conda] numpy 1.21.3 pypi_0 pypi
[conda] torch 2.5.0.dev20240901 pypi_0 pypi
[conda] torchaudio 2.5.0.dev20240901 pypi_0 pypi
[conda] torchsr 1.0.4 pypi_0 pypi
[conda] torchvision 0.20.0.dev20240901 pypi_0 pypi

[davidlin54]

@angelayi this seems to be related to pytorch/pytorch#115092, are there any updates on fixing this bug?