limit kain to run 2 more than maxsub. Might reduce noise at the end … #1507

Job	Run time
macos-latest: clang++ Release Threads	12m 44s
macos-latest: clang++ Release OneTBB	3m 58s
macos-latest: clang++ Release PaRSEC	2m 28s
ubuntu-20.04: /usr/bin/g++-9 Release Threads	29m 47s
ubuntu-20.04: /usr/bin/g++-9 Release OneTBB	2m 7s
ubuntu-20.04: /usr/bin/g++-9 Release PaRSEC	2m 44s
macos-latest: clang++ Debug Threads	15m 7s
macos-latest: clang++ Debug OneTBB	3m 41s
macos-latest: clang++ Debug PaRSEC	3m 25s
ubuntu-20.04: /usr/bin/g++-9 Debug Threads	29m 14s
ubuntu-20.04: /usr/bin/g++-9 Debug OneTBB	1m 49s
ubuntu-20.04: /usr/bin/g++-9 Debug PaRSEC	2m 43s
	1h 49m 47s

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