[release/2.13] dynamo\test_streams_xpu.py::TestStreams::test_epilogue_copy_streams_external AssertionError

### 🐛 Describe the bug

Cases:
op_ut,third_party.torch-xpu-ops.test.xpu.dynamo.test_streams_xpu.TestStreams,test_epilogue_copy_streams_external

**Error Message**
```
AssertionError: "Mutations on inputs with user-specified streams are not yet supported" does not match "backend='' raised:
```

### Versions

Click to expand environment details

```
PyTorch version: 2.13.0+xpu
Is debug build: False
CUDA used to build PyTorch: None
ROCM used to build PyTorch: N/A

OS: Microsoft Windows 11 Pro (10.0.26100 64-bit)
GCC version: Could not collect
Clang version: Could not collect
CMake version: version 3.31.6
Libc version: N/A

Python version: 3.12.13 | packaged by conda-forge | (main, Mar 5 2026, 16:36:12) [MSC v.1944 64 bit (AMD64)] (64-bit runtime)
Python platform: Windows-11-10.0.26100-SP0
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
Is XPU available: True
XPU used to build PyTorch: 20260000
Intel GPU driver version:
* 32.0.101.8826 (20260529000000.******+***)
Intel GPU models onboard:
* Intel(R) Arc(TM) B580 Graphics
Intel GPU models detected:
* [0] _XpuDeviceProperties(name='Intel(R) Arc(TM) B580 Graphics', platform_name='Intel(R) oneAPI Unified Runtime over Level-Zero V2', type='gpu', device_id=0xE20B, uuid=86800be2-0000-0000-0300-000000000000, driver_version='1.15.37858', total_memory=11875MB, local_mem_size=128KB, last_level_cache_size=18432KB, max_compute_units=160, memory_clock_rate=0MHz, memory_bus_width=64-bit, gpu_eu_count=160, gpu_subslice_count=20, max_work_group_size=1024, max_num_sub_groups=64, sub_group_sizes=[16 32], has_fp16=1, has_fp64=1, has_atomic64=1, is_integrated_gpu=0)
HIP runtime version: N/A
MIOpen runtime version: N/A
Is XNNPACK available: False
Caching allocator config: N/A

CPU:
Name: 13th Gen Intel(R) Core(TM) i5-13400
Manufacturer: GenuineIntel
Family: 205
Architecture: 9
ProcessorType: 3
DeviceID: CPU0
CurrentClockSpeed: 2500
MaxClockSpeed: 2500
L2CacheSize: 9728
L2CacheSpeed: None
Revision: None

Versions of relevant libraries:
[pip3] dpcpp-cpp-rt==2026.0.0
[pip3] intel-cmplr-lib-rt==2026.0.0
[pip3] intel-cmplr-lib-ur==2026.0.0
[pip3] intel-cmplr-lic-rt==2026.0.0
[pip3] intel-opencl-rt==2026.0.0
[pip3] intel-openmp==2026.0.0
[pip3] intel-pti==0.17.0
[pip3] intel-sycl-rt==2026.0.0
[pip3] mkl==2026.0.0
[pip3] mkl-include==2024.2.0
[pip3] mkl-static==2024.2.0
[pip3] mypy_extensions==1.1.0
[pip3] numpy==1.26.2
[pip3] onemkl-license==2026.0.0
[pip3] onemkl-sycl-blas==2026.0.0
[pip3] onemkl-sycl-dft==2026.0.0
[pip3] onemkl-sycl-lapack==2026.0.0
[pip3] onemkl-sycl-rng==2026.0.0
[pip3] onemkl-sycl-sparse==2026.0.0
[pip3] onnx==1.21.0
[pip3] onnx-ir==0.1.16
[pip3] onnxscript==0.6.2
[pip3] optree==0.13.0
[pip3] tbb==2023.0.0
[pip3] tbb-devel==2021.13.1
[pip3] tcmlib==1.5.0
[pip3] torch==2.13.0+xpu
[pip3] torchaudio==2.11.0+xpu
[pip3] torchmetrics==1.9.0
[pip3] torchrec-nightly==2022.4.26
[pip3] torchvision==0.28.0+xpu
[pip3] torchviz==0.0.3
[pip3] torchx-nightly==2026.6.11
[pip3] triton-xpu==3.7.2
[pip3] umf==1.1.0
[conda] dpcpp-cpp-rt 2026.0.0 pypi_0 pypi
[conda] intel-cmplr-lib-rt 2026.0.0 pypi_0 pypi
[conda] intel-cmplr-lib-ur 2026.0.0 pypi_0 pypi
[conda] intel-cmplr-lic-rt 2026.0.0 pypi_0 pypi
[conda] intel-opencl-rt 2026.0.0 pypi_0 pypi
[conda] intel-openmp 2026.0.0 pypi_0 pypi
[conda] intel-pti 0.17.0 pypi_0 pypi
[conda] intel-sycl-rt 2026.0.0 pypi_0 pypi
[conda] mkl 2026.0.0 pypi_0 pypi
[conda] mkl-include 2024.2.0 pypi_0 pypi
[conda] mkl-static 2024.2.0 pypi_0 pypi
[conda] numpy 1.26.2 pypi_0 pypi
[conda] onemkl-license 2026.0.0 pypi_0 pypi
[conda] onemkl-sycl-blas 2026.0.0 pypi_0 pypi
[conda] onemkl-sycl-dft 2026.0.0 pypi_0 pypi
[conda] onemkl-sycl-lapack 2026.0.0 pypi_0 pypi
[conda] onemkl-sycl-rng 2026.0.0 pypi_0 pypi
[conda] onemkl-sycl-sparse 2026.0.0 pypi_0 pypi
[conda] optree 0.13.0 pypi_0 pypi
[conda] tbb 2023.0.0 pypi_0 pypi
[conda] tbb-devel 2021.13.1 pypi_0 pypi
[conda] tcmlib 1.5.0 pypi_0 pypi
[conda] torch 2.13.0+xpu pypi_0 pypi
[conda] torchaudio 2.11.0+xpu pypi_0 pypi
[conda] torchmetrics 1.9.0 pypi_0 pypi
[conda] torchrec-nightly 2022.4.26 pypi_0 pypi
[conda] torchvision 0.28.0+xpu pypi_0 pypi
[conda] torchviz 0.0.3 pypi_0 pypi
[conda] torchx-nightly 2026.6.11 pypi_0 pypi
[conda] triton-xpu 3.7.2 pypi_0 pypi
[conda] umf 1.1.0 pypi_0 pypi
```