[CI/Build] Add CI config for Sonic MoE kernel tests on H100

[clocksmith]

Purpose

Adds buildkite CI configuration to run Sonic MoE kernel tests on H100 GPUs.

This config installs the sonicmoe package and executes tests/kernels/test_sonic_moe.py, when relevant source files change.

Unblocks #31548 (Sonic MoE integration for Hopper GPUs) by enabling CI validation.

Unblocks #31039.

Test Plan

CI-only change. The test configuration will trigger when #31548 is rebased/merged after this PR merges:

• source_file_dependencies matches files added in [Kernel] Add Sonic MoE integration for Hopper GPUs #31548
• Test runs pip install sonicmoe then pytest -v -s kernels/test_sonic_moe.py

Test Result

N/A - CI configuration change. Validation occurs when #31548 runs against updated CI.

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Essential Elements of an Effective PR Description Checklist

• The purpose of the PR, such as "Fix some issue (link existing issues this PR will resolve)".
• The test plan, such as providing test command.
• The test results, such as pasting the results comparison before and after, or e2e results

[github-actions]

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You ask your reviewers to trigger select CI tests on top of fastcheck CI.

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[gemini-code-assist]

Code Review

This pull request adds a new CI configuration to run Sonic MoE kernel tests on H100 GPUs. The change is straightforward, but I've found a potential issue in the pytest command path that could prevent the tests from running correctly. I've also suggested adding a working_dir to ensure consistency with other kernel tests.

[LucasWilkinson]

kernels/moe/test_sonic_moe.py does not exist until #31548 is merged, its better to just add this to the PR that introduces the test. Why does this need its own build step? 45min is a very long timeout for a basic kernel test, does it actually take this long? if so we try to shorten this to save on CI costs.

[clocksmith]

kernels/moe/test_sonic_moe.py does not exist until #31548 is merged, its better to just add this to the PR that introduces the test. Why does this need its own build step? 45min is a very long timeout for a basic kernel test, does it actually take this long? if so we try to shorten this to save on CI costs.

OK, closing this PR. I misunderstood the CI workflow and thought the sonicmoe dependency had to be installed before the test could run, not realizing the CI config itself handles pip install sonicmoe in the commands block.

Anywho, moved the config into #31548 so the test file and CI land together. Reduced timeout to 10min. Happy to combine with the DeepGEMM H100 step (or another) if you prefer to avoid a separate build step, however I think the isolation is worth the cost, since there are several sepearet build steps w/ H100 already. Thanks!