Having these named differently than the test itself mostly creates
unecessary confusion and makes writing logic against the tests harder
so let's rename the testsuite-xx units and scripts to just use the
test name itself.
Let's take a step back and revert back to the original behavior where we
exit on a first failing subtest. The current behavior makes fishing out the
failing test details quite unpleasant, and in certain situations the
journal may even be rotated away so we end up with no actionable logs.
Since bash has no namespaces, let's do the second best thing and prefix
all "internal" stuff with an underscore, to minimize the chance of a name
conflict in the future.
