[BugFix] Re-enable Blackwell

[LucasWilkinson]

#18562 accidentally disabled Blackwell, re-enable it

[github-actions]

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[tlrmchlsmth]

Let's run the 11.8 build out of abundance of caution

[simon-mo]

https://buildkite.com/vllm/ci/builds/20576/steps?jid=0196f99a-8f32-44c2-8667-f60e393ecfdf#0196f99a-8f32-44c2-8667-f60e393ecfdf/129-5600
[2025-05-22T20:46:03Z] #29 27.54 nvcc fatal : Unsupported gpu architecture 'compute_100'
😢

[LucasWilkinson]

https://buildkite.com/vllm/ci/builds/20576/steps?jid=0196f99a-8f32-44c2-8667-f60e393ecfdf#0196f99a-8f32-44c2-8667-f60e393ecfdf/129-5600 [2025-05-22T20:46:03Z] #29 27.54 nvcc fatal : Unsupported gpu architecture 'compute_100' 😢

Seems like its not respecting: TORCH_CUDA_ARCH_LIST

[2025-05-22T20:45:44Z] #29 8.542 CMake Warning at /usr/local/lib/python3.12/dist-packages/torch/share/cmake/Caffe2/public/utils.cmake:328 (message):
[2025-05-22T20:45:44Z] #29 8.542   In the future we will require one to explicitly pass TORCH_CUDA_ARCH_LIST
[2025-05-22T20:45:44Z] #29 8.542   to cmake instead of implicitly setting it as an env variable.  This will
[2025-05-22T20:45:44Z] #29 8.542   become a FATAL_ERROR in future version of pytorch.

[LucasWilkinson]

superseded by #18579