[ROCm] do not use __shfl sync functions

[jeffdaily]

This avoids a static_assert compile-time failure for HIP.

[jeffdaily]

pytest results on an MI200 system. 2801 passed, 1 warning in 11.85s.

/opt/conda/envs/py_3.10/lib/python3.10/site-packages/hypothesis/entry_points.py:23: UserWarning: pkg_resources is deprecated as an API. See https://setuptools.pypa.io/en/latest/pkg_resources.html. The pkg_resources package is slated for removal as early as 2025-11-30. Refrain from using this package or pin to Setuptools<81.
  import pkg_resources
============================================================================================================================ test session starts =============================================================================================================================
platform linux -- Python 3.10.18, pytest-7.3.2, pluggy-1.6.0
rootdir: /var/lib/jenkins/pytorch_scatter
configfile: setup.cfg
plugins: flakefinder-1.1.0, hypothesis-5.35.1, xdist-3.3.1, subtests-0.13.1, xdoctest-1.1.0, cpp-2.3.0, rerunfailures-14.0
collected 2801 items

test_broadcasting.py ..........
test_gather.py ....................................................................................................................................................................................................................................
test_multi_gpu.py ..............................
test_scatter.py ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
test_segment.py ....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
test_zero_tensors.py ....................
composite/test_logsumexp.py ..
composite/test_softmax.py ..
composite/test_std.py .

============================================================================================================================== warnings summary ==============================================================================================================================
test/composite/test_std.py::test_std
  /var/lib/jenkins/pytorch_scatter/test/composite/test_std.py:12: UserWarning: Converting a tensor with requires_grad=True to a scalar may lead to unexpected behavior.
  Consider using tensor.detach() first. (Triggered internally at /var/lib/jenkins/pytorch/torch/csrc/autograd/generated/python_variable_methods.cpp:835.)
    expected = torch.tensor([[std, 0], [0, std]])

-- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html
====================================================================================================================== 2801 passed, 1 warning in 11.85s ======================================================================================================================

[codecov-commenter]

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Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.20%. Comparing base (140d3ad) to head (7b17897).
Report is 18 commits behind head on master.

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Additional details and impacted files

@@            Coverage Diff             @@
##           master     #493      +/-   ##
==========================================
+ Coverage   97.23%   98.20%   +0.97%     
==========================================
  Files          10       10              
  Lines         217      223       +6     
==========================================
+ Hits          211      219       +8     
+ Misses          6        4       -2     

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