Copy some extra test infrastructure from the mutexfree-shmlock branch to trunk.
FossilOrigin-Name: 883337ffdb434b6856ceaada121c0be67e2fdec7b447675f45e85568ef28d7d9
D
dan committed
94e95ea46e89f34adeba606db60f4691a25d7c1f
Parent: 29e9af8