chore(ci): migrate Linux CI to runs-on self-hosted runners #5973

Job	Run time
check-xarray-docs	14s
build-wheels-free-threaded	3m 50s
build-wheels	3m 50s
stubtest	17s
test-hypothesis-shard (1)	4m 38s
xarray-backends (latest-release, latest-release, latest-release)	1m 28s
xarray-backends (minimum, 2025.07.1, 3.1.0)	1m 23s
test (minimum, 2025.07.1, 2025.2.0, 2025.2.0, 3.1.0)	1m 53s
test-hypothesis-shard (2)	3m 18s
test-hypothesis-shard (0)	52s
test (latest, latest-release, latest-release, latest-release, latest-release)	1m 42s
compat-stateful	2m 29s
test-free-threaded	2m 19s
test-hypothesis	5s
	28m 18s

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