While the discussion about how to refactor test framework is not
finished (#1654), make this change: move `rm -rf build` in the
beginning of the test. For these reasons:
* it is useful to inspect the contents of the `build` directory
especially after the test failure
* if build crashes mid-test (e.g. process killed), next run should
not be affected by the `build` directory from the previous run
This involves making 'unelab' aware of nested names so that it can
remove the parameters from names in the current block. It's a bit of a
hacky solution, but it is also the easiest one.
Ideally we'd build the getter types directly, rather than using unelab,
but that's one to save for another time.
Fixes#1482
