experiment: raise SubStepErrors on plumbum exceptions
experiment: raise SubStepErrors on plumbum exceptions

Former-commit-id: a0eb32cd5b6352034a1cd012c5d19d3f36e08a84
Former-commit-id: 72f13189b30b880b15b2aefea71d62a173a3b202 [formerly 9b67086c8575972f1b1ba6c9256a9188b43bb6e1] [formerly 6cc87758800a4422eabf6959b526d9751ec04bea [formerly ce71a389935c0d6fb0c214f0432b972dd9eb7371]]
Former-commit-id: 5c0c266f83f45cb54ba29ce9161039d825afb7a4 [formerly 64113075740b235f21a2d246b721cc6bfd728c27]
Former-commit-id: fdc9ac316d973585d741ee019313875623e5e29a
PolyJIT/benchbuild,PolyJIT/benchbuild,PolyJIT/benchbuild,PolyJIT/benchbuild