testsuite: Fix and extend closure_size test
This was previously broken in several ways. This is fixed and it also
now tests arrays. Unfortunately I was unable to find a way to continue
testing PAP and FUN sizes; these simply depend too much upon the
behavior of the simplifier.
I also tried to extend this to test non-empty arrays as well but
unfortunately this was non-trivial as the array card size constant isn't
readily available from haskell.
Fixes Trac #16531.