Adding Dirac point caching test with moving mesh.

The Dirac points leave the domain (and hence become deactivated)
in this test.

Refs #2364.
Caching only Dirac point data for local elements

This seems to fix the moving-mesh-in-parallel case, but introduced
some new strangeness in the adaptivity tests.  It is working for the
moment but I don't think it's quite ready to merge yet.

Refs #2364.