Improve the skip condition for cuFile binding tests

[leofang]

During the bring-up #684 we noticed that some cuFile bindings require the internal thread pool to be activated, but on some systems they are not activated by default (for reasons I don't fully understand yet). We had to provide a custom json file pointed to by an env var CUFILE_ENV_PATH_JSON to enforce the activation and make the tests pass on this local system.

We should consider either or both of the following approaches:

1. Encode the activation criteria as a pytest skip decorator, so that the tests that need the threadpool to pass would be skipped
2. Add a cufile.json file to the test directory (either statically or dynamically) and set up CUFILE_ENV_PATH_JSON to force activating the thread pool

[leofang]

cc @sourabgupta3 for vis

[leofang]

Discussed offline. We also need to apply the WSL detection and skip the tests on WSL, which is not officially supported by cuFile yet.

cuda-python/cuda_core/tests/test_event.py

Lines 27 to 28 in 4c21824

	def platform_is_wsl():
	return platform.system() == "Linux" and "microsoft" in pathlib.Path("/proc/version").read_text().lower()

[rwgk]

This was resolved by #778