Retiring this future by making it a NOTEST

This was marked as a bug future due to its nondeterminism; this isn't
really appropriate -- it should've been marked as a NOTEST since it
isn't a bug in Chapel itself.  Doing that now.
Merge pull request #401 from bradcray/retire-dpll

Retiring this future by making it a NOTEST

This was marked as a bug future due to its nondeterminism; this isn't
really appropriate -- it should've been marked as a NOTEST since it
isn't a bug in Chapel itself. Doing that now.