This gives us much more room for activities.
It makes sense to keep the test disk small: easier parallelization,
heavier emubd with more test features, and if you're running into space
issues in a test, that usually just means you need to be more creative
with how the test is setup.
But for benches, we're interested what happens when we throw a ton of
data at the system.
Also defaulted to noop erases. 0xff erases behave more predictably,
which is useful for testing. But for benching, less work is faster.
Christopher Haster
fec5b36357