commented out petsc4py test that breaks cygwin

apologies, another problem on cygwin where the only solution I can work out right now is to comment out the tests. petsc4py is properly installed and proteus runs fine in serial and parallel from a prefix installed with 'hit develop ...'. The problem is the post-install buildstage for testing, which can't load PETSc.dll.  I tried several permutations of setting PATH and PYTHONPATH to no avail. PETSc.dll where python things it is, it just can't load it.