[CI] Remove testing on 6, 8, 15, 16 threads (#396) #2453

Job	Run time
python-lint	6s
clang-format	8s
macos-clang-build	2m 7s
ubuntu-clang-build (ubuntu-24.04-arm)	2m 39s
ubuntu-clang-build (ubuntu-24.04)	1m 55s
ubuntu-gcc-build (ubuntu-24.04-arm)	3m 3s
ubuntu-gcc-build (ubuntu-24.04)	1m 17s
windows-msvc-build	3m 29s
windows-clang-build	2m 19s
macos-clang-test	2m 58s
windows-clang-test	1m 26s
windows-msvc-test	2m 20s
windows-clang-test-extended	1m 15s
ubuntu-clang-sanitizer-build (ubuntu-24.04)	1m 59s
ubuntu-clang-test (ubuntu-24.04)	4m 25s
ubuntu-clang-test (ubuntu-24.04-arm)	5m 25s
ubuntu-gcc-test (ubuntu-24.04)	4m 19s
ubuntu-gcc-test (ubuntu-24.04-arm)	5m 14s
macos-clang-test-extended	2m 5s
windows-msvc-test-extended	1m 17s
ubuntu-clang-sanitizer-test (ubuntu-24.04)	2m 28s
ubuntu-clang-sanitizer-test-extended (ubuntu-24.04)	57s
ubuntu-clang-test-extended (ubuntu-24.04)	2m 41s
ubuntu-clang-test-extended (ubuntu-24.04-arm)	4m 26s
ubuntu-gcc-test-extended (ubuntu-24.04-arm)	3m 28s
ubuntu-gcc-test-extended (ubuntu-24.04)	2m 33s
ubuntu-gcc-build-codecov	3m 26s
ubuntu-gcc-build-perf-stats	0s
	1h 9m 45s

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