Fix clock start logic. #12467

Job	Run time
build_details	6s
build_opam (4.14.x)	3m 57s
build_js	1m 18s
build_opam (5.3.x)	4m 42s
build_no_depopts	3m 18s
tree_sitter_parse	1m 6s
lezer_parse	45s
run_tests (@citest)	8m 20s
build_posix (ubuntu_oracular, arm64)	9m 43s
run_tests (@mediatest)	8m 30s
build_posix (ubuntu_noble, amd64)	8m 48s
build_posix (debian_bookworm, amd64)	8m 20s
build_posix (debian_trixie, arm64)	9m 35s
build_win32 (x64)	11m 53s
build_posix (debian_trixie, amd64)	8m 30s
build_posix (ubuntu_oracular, amd64)	8m 44s
build_posix (ubuntu_noble, arm64)	9m 51s
run_tests (@doctest)	4m 27s
update_doc	0s
build_posix (debian_bookworm, arm64)	9m 44s
build_posix (alpine, arm64)	6m 32s
build_posix (alpine, amd64)	6m 2s
fetch_s3_artifacts	29s
build_docker (amd64)	1m 35s
build_docker_minimal (amd64)	1m 30s
build_docker_alpine (arm64)	49s
build_docker_alpine (amd64)	45s
build_docker_minimal (arm64)	1m 40s
build_docker (arm64)	2m 42s
build_docker_alpine_minimal (amd64)	43s
build_docker_alpine_minimal (arm64)	45s
update_release	0s
build_docker_release-minimal	-1s
build_docker_release	0s
	2h 25m 8s

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