TaskQualifier::*_sync does not work for iterative task lists

[lroberts36]

When TaskRegion::BuildGraph is called, it connects regional tasks across all of the task lists in TaskRegion::task_lists but does not appear to do anything with the task lists contained in TaskList::sublists. As a result, the BiCGSTAB solver hangs for more than one partition since the residual is zeroed out by one task for a reduction before other tasks have the chance to check the residual in their completion task in the previous iteration.

I will try to take a look at how to fix this next week.