The memory leaks reported for the tests QVTK-TestQtTableModelAdapter
and QVTK-TestQtTreeModelAdapter have been present for months. Since no
one has tried to repair them, this patch suppresses them. They do not
appear to be critical to VTK, but their presence dilutes the
effectiveness of the valgrind reporting.

Change-Id: Iae03e2b8fc7d68c1acc51ca0965f5c187fb65250