test: cover GetNumThreads default #2902

Job	Run time
lint / python-lint	6s
lint / clang-format	8s
mac / macos-clang-build	2m 12s
ubuntu / ubuntu-gcc-build (ubuntu-24.04-arm)	2m 55s
ubuntu / ubuntu-gcc-build (ubuntu-24.04)	2m 20s
mac / macos-clang-build-debug	3m 9s
ubuntu / ubuntu-clang-build (ubuntu-24.04)	1m 17s
windows / windows-msvc-build	2m 46s
ubuntu / ubuntu-clang-build (ubuntu-24.04-arm)	3m 20s
windows / windows-msvc-build-debug	5m 33s
windows / windows-clang-build	3m 19s
ubuntu / ubuntu-gcc-build-debug (ubuntu-24.04)	1m 3s
mac / macos-clang-test	2m 51s
windows / windows-msvc-test-extended	0s
windows / windows-msvc-test	0s
ubuntu / ubuntu-clang-sanitizer-build (ubuntu-24.04)	1m 22s
ubuntu / ubuntu-clang-test (ubuntu-24.04-arm)	5m 15s
ubuntu / ubuntu-clang-test (ubuntu-24.04)	4m 51s
windows / windows-clang-test	0s
windows / windows-clang-test-extended	0s
ubuntu / ubuntu-gcc-test (ubuntu-24.04)	5m 16s
ubuntu / ubuntu-gcc-test (ubuntu-24.04-arm)	4m 45s
mac / macos-clang-test-extended	2m 25s
ubuntu / ubuntu-clang-sanitizer-test (ubuntu-24.04)	3m 1s
ubuntu / ubuntu-clang-test-extended (ubuntu-24.04)	2m 55s
ubuntu / ubuntu-clang-test-extended (ubuntu-24.04-arm)	4m 12s
ubuntu / ubuntu-gcc-test-extended (ubuntu-24.04-arm)	3m 4s
ubuntu / ubuntu-gcc-test-extended (ubuntu-24.04)	2m 43s
ubuntu / ubuntu-clang-sanitizer-test-extended (ubuntu-24.04)	1m 40s
ubuntu / ubuntu-gcc-build-codecov	3m 50s
perf	0s
	1h 16m 18s

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