possibly correct #1389

Job	Run time
macos-latest: clang++ Release Threads	26m 13s
macos-latest: clang++ Release OneTBB	3m 59s
macos-latest: clang++ Release PaRSEC	3m 18s
ubuntu-20.04: /usr/bin/g++-9 Release Threads	25m 47s
ubuntu-20.04: /usr/bin/g++-9 Release OneTBB	3m 50s
ubuntu-20.04: /usr/bin/g++-9 Release PaRSEC	1m 28s
macos-latest: clang++ Debug Threads	13m 27s
macos-latest: clang++ Debug OneTBB	4m 15s
macos-latest: clang++ Debug PaRSEC	3m 28s
ubuntu-20.04: /usr/bin/g++-9 Debug Threads	25m 8s
ubuntu-20.04: /usr/bin/g++-9 Debug OneTBB	2m 48s
ubuntu-20.04: /usr/bin/g++-9 Debug PaRSEC	1m 54s
	1h 55m 35s

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