Range-diff !454

back to !454 e2e: build binaries once, run the tests in parallel

1:  cd4bd81 = 1:  d2fa3c3 e2e: build each binary once per process
2:  97b140d = 2:  76df812 e2e: run the tests in parallel
3:  ed5a6b0 = 3:  abe9818 e2e: drop the minimum-timeout guard