`NIOFileSystem`: Try ${TMPDIR} first for temporary directory #1223

Job	Run time
Construct integration test matrix	3s
Vsock tests	2m 18s
Benchmarks / Construct Benchmarks matrix	5s
Cxx interop / Construct Cxx interop matrix	3s
Unit tests / Construct unit test matrix	3s
Soundness / API breakage check	2m 6s
Soundness / Documentation check	2m 10s
Soundness / Unacceptable language check	2s
Soundness / License headers check	9s
Soundness / Broken symlinks check	3s
Soundness / Format check	48s
Soundness / Python lint check	5s
Soundness / Shell check	35s
Soundness / YAML lint check	5s
Cxx interop / Cxx interop / Linux (5.9)	1m 12s
Cxx interop / Cxx interop / Linux (5.10)	1m 7s
Cxx interop / Cxx interop / Linux (6.0)	1m 22s
Unit tests / Unit tests / Linux (5.9)	3m 48s
Cxx interop / Cxx interop / Linux (nightly-6.0)	1m 33s
Unit tests / Unit tests / Linux (5.10)	3m 45s
Cxx interop / Cxx interop / Linux (nightly-main)	1m 29s
Integration tests / Linux (5.9)	22m 54s
Unit tests / Unit tests / Linux (6.0)	4m 13s
Integration tests / Linux (5.10)	21m 16s
Unit tests / Unit tests / Linux (nightly-6.0)	4m 33s
Integration tests / Linux (6.0)	23m 34s
Unit tests / Unit tests / Linux (nightly-main)	4m 26s
Integration tests / Linux (nightly-6.0)	23m 53s
Integration tests / Linux (nightly-main)	23m 17s
Benchmarks / Benchmarks / Linux (5.9)	5m 33s
Benchmarks / Benchmarks / Linux (5.10)	5m 1s
Benchmarks / Benchmarks / Linux (6.0)	5m 18s
Benchmarks / Benchmarks / Linux (nightly-6.0)	6m 14s
Benchmarks / Benchmarks / Linux (nightly-main)	4m 17s
	2h 57m 20s

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