Don't create a new state dumper on suite reload.

Since 9d5b7e9 we were creating a new state dumper on reload, but not
giving the new instance a reference to the task pool, which resulted
in truncated state dumps (no task states).
Added a test for restart after reload.
Merge pull request #913 from hjoliver/fix-post-reload-state-dumping

Fix post-reload state dumping