Run (most) CUDA tests in pixi

[crusaderky]

Add a pixi task to run CUDA tests.
Note that this does not run on github actions as there are no CUDA-enabled VMs in the free tier.

Known issues

• Could not test dask-cuda and dask-cudf, as they contain an exact pin of dask-core which conflicts with version 2099.0.0 set by ../dask/pixi.toml. A workaround could have been to write ad-hoc pixi-build recipes for these two projects but it felt like overengineering to me.
• distributed/diagnostics/tests/test_nvml.py::test_visible_devices_uuid fails on my RTX 3080 on Linux 64 due to an upstream issue in pynvml:

>>> import pynvml
>>> pynvml.nvmlInit()
>>> h = pynvml.nvmlDeviceGetHandleByIndex(0)
>>> pynvml.nvmlDeviceGetSerial(h)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
    pynvml.nvmlDeviceGetSerial(h)
    ~~~~~~~~~~~~~~~~~~~~~~~~~~^^^
  File "/home/crusaderky/github/distributed/.pixi/envs/cuda/lib/python3.14/site-packages/pynvml.py", line 2946, in wrapper
    res = func(*args, **kwargs)
  File "/home/crusaderky/github/distributed/.pixi/envs/cuda/lib/python3.14/site-packages/pynvml.py", line 3345, in nvmlDeviceGetSerial
    _nvmlCheckReturn(ret)
    ~~~~~~~~~~~~~~~~^^^^^
  File "/home/crusaderky/github/distributed/.pixi/envs/cuda/lib/python3.14/site-packages/pynvml.py", line 1098, in _nvmlCheckReturn
    raise NVMLError(ret)
pynvml.NVMLError_NotSupported: Not Supported

[crusaderky]

FYI @rjzamora @quasiben

[github-actions]

Unit Test Results

See test report for an extended history of previous test failures. This is useful for diagnosing flaky tests.

    3 files   -     1      3 suites   - 1   0s ⏱️ ±0s
4 101 tests  -     4  3 902 ✅  -    35  196 💤 +32  3 ❌  - 1 
6 778 runs   - 2 731  6 405 ✅  - 2 636  370 💤  - 94  3 ❌  - 1 

For more details on these failures, see this check.

Results for commit 9cba932. ± Comparison against base commit 4578e5d.

This pull request removes 23 and adds 19 tests. Note that renamed tests count towards both.

distributed.diagnostics.tests.test_memray ‑ test_all_workers
distributed.diagnostics.tests.test_memray ‑ test_basic_integration_scheduler
distributed.diagnostics.tests.test_memray ‑ test_basic_integration_scheduler_report_args[False]
distributed.diagnostics.tests.test_memray ‑ test_basic_integration_scheduler_report_args[report_args0]
distributed.diagnostics.tests.test_memray ‑ test_basic_integration_workers[1]
distributed.diagnostics.tests.test_memray ‑ test_basic_integration_workers[False]
distributed.diagnostics.tests.test_memray ‑ test_basic_integration_workers[True]
distributed.diagnostics.tests.test_memray ‑ test_basic_integration_workers_report_args[False]
distributed.diagnostics.tests.test_memray ‑ test_basic_integration_workers_report_args[report_args0]
distributed.diagnostics.tests.test_nvml ‑ test_2_visible_devices[0,1]
…

distributed.cli.tests.test_dask_scheduler ‑ test_signal_handling[Signals.SIGINT]
distributed.cli.tests.test_dask_scheduler ‑ test_signal_handling[Signals.SIGTERM]
distributed.cli.tests.test_dask_spec ‑ test_signal_handling_scheduler[Signals.SIGINT]
distributed.cli.tests.test_dask_spec ‑ test_signal_handling_scheduler[Signals.SIGTERM]
distributed.cli.tests.test_dask_spec ‑ test_signal_handling_worker[Signals.SIGINT-Nanny]
distributed.cli.tests.test_dask_spec ‑ test_signal_handling_worker[Signals.SIGINT-Worker]
distributed.cli.tests.test_dask_spec ‑ test_signal_handling_worker[Signals.SIGTERM-Nanny]
distributed.cli.tests.test_dask_spec ‑ test_signal_handling_worker[Signals.SIGTERM-Worker]
distributed.cli.tests.test_dask_worker ‑ test_signal_handling[Signals.SIGINT---nanny]
distributed.cli.tests.test_dask_worker ‑ test_signal_handling[Signals.SIGINT---no-nanny]
…

This pull request removes 12 skipped tests and adds 13 skipped tests. Note that renamed tests count towards both.

distributed.diagnostics.tests.test_nvml ‑ test_2_visible_devices[0,1]
distributed.diagnostics.tests.test_nvml ‑ test_2_visible_devices[1,0]
distributed.diagnostics.tests.test_nvml ‑ test_gpu_metrics
distributed.diagnostics.tests.test_nvml ‑ test_gpu_monitoring_range_query
distributed.diagnostics.tests.test_nvml ‑ test_gpu_monitoring_recent
distributed.diagnostics.tests.test_nvml ‑ test_has_cuda_context
distributed.diagnostics.tests.test_nvml ‑ test_one_time
distributed.diagnostics.tests.test_nvml ‑ test_one_visible_devices
distributed.diagnostics.tests.test_nvml ‑ test_visible_devices_bad_uuid
distributed.diagnostics.tests.test_nvml ‑ test_visible_devices_uuid
…

distributed.cli.tests.test_dask_scheduler ‑ test_signal_handling[Signals.SIGINT]
distributed.cli.tests.test_dask_scheduler ‑ test_signal_handling[Signals.SIGTERM]
distributed.cli.tests.test_dask_spec ‑ test_signal_handling_scheduler[Signals.SIGINT]
distributed.cli.tests.test_dask_spec ‑ test_signal_handling_scheduler[Signals.SIGTERM]
distributed.cli.tests.test_dask_spec ‑ test_signal_handling_worker[Signals.SIGINT-Nanny]
distributed.cli.tests.test_dask_spec ‑ test_signal_handling_worker[Signals.SIGINT-Worker]
distributed.cli.tests.test_dask_spec ‑ test_signal_handling_worker[Signals.SIGTERM-Nanny]
distributed.cli.tests.test_dask_spec ‑ test_signal_handling_worker[Signals.SIGTERM-Worker]
distributed.cli.tests.test_dask_worker ‑ test_signal_handling[Signals.SIGINT---nanny]
distributed.cli.tests.test_dask_worker ‑ test_signal_handling[Signals.SIGINT---no-nanny]
…

This pull request skips 37 and un-skips 6 tests.

distributed.cli.tests.test_dask_scheduler ‑ test_uvloop
distributed.cli.tests.test_dask_spec ‑ test_uvloop
distributed.cli.tests.test_dask_worker ‑ test_uvloop[--nanny]
distributed.cli.tests.test_dask_worker ‑ test_uvloop[--no-nanny]
distributed.tests.test_client ‑ test_allow_restrictions
distributed.tests.test_client ‑ test_client_num_fds
distributed.tests.test_client ‑ test_client_replicate_host
distributed.tests.test_client ‑ test_file_descriptors_dont_leak[Nanny]
distributed.tests.test_client ‑ test_file_descriptors_dont_leak[Worker]
distributed.tests.test_client ‑ test_mixed_compression
…

distributed.dashboard.tests.test_scheduler_bokeh ‑ test_counters
distributed.dashboard.tests.test_worker_bokeh ‑ test_counters
distributed.deploy.tests.test_subprocess ‑ test_raise_on_windows
distributed.shuffle.tests.test_shuffle ‑ test_handle_null_partitions_2
distributed.tests.test_core ‑ test_tick_logging
distributed.tests.test_core ‑ test_ticks