tests: Tweaks to health checks and examples ...

The time-based health checks keep causing transient test failures,
especially when my host system is under load. Throw them away.

Also drop the max examples for long down. CI is already taking an hour,
so I assume long is going to take days.

tests: Add SPDX license headers

tests: Add 'long' test profile target ...

This is mainly so I can run it while I'm not busy to try and catch
obscure bugs.

tests: Tune Hypothesis max_examples ...

On my machine, 100 for dev is pretty useful and takes 6.6 seconds.
For CI, 100000 takes 660 seconds.

tests: Dump pytest-timeout and clean up conftest ...

pytest-timeout just didn't integrate properly with Hypothesis, and it
was more trouble than it's worth. Dump it.

make: Add test_verbose and test_long targets