Distributed findImplicitGeometricCouplingEntries
Distributed findImplicitGeometricCouplingEntries

If we're on a distributed mesh, we might not be able to access every
node, and we need to handle the cases where we can't.

I don't understand this code's downstream uses well enough to
*perfectly* parallelize it, so I'm doing some all-to-all communication
which isn't as efficient as it should be but which should ensure
correctness.

This fixes more test failures in #1500 for me

dschwen/moose,milljm/moose,friedmud/moose,nuclear-wizard/moose,friedmud/moose,andrsd/moose,bwspenc/moose,lindsayad/moose,idaholab/moose,harterj/moose,yipenggao/moose,laagesen/moose,liuwenf/moose,SudiptaBiswas/moose,SudiptaBiswas/moose,SudiptaBiswas/moose,andrsd/moose,bwspenc/moose,laagesen/moose,lindsayad/moose,liuwenf/moose,nuclear-wizard/moose,liuwenf/moose,bwspenc/moose,bwspenc/moose,jessecarterMOOSE/moose,idaholab/moose,harterj/moose,backmari/moose,sapitts/moose,sapitts/moose,laagesen/moose,idaholab/moose,backmari/moose,SudiptaBiswas/moose,YaqiWang/moose,nuclear-wizard/moose,laagesen/moose,bwspenc/moose,milljm/moose,andrsd/moose,backmari/moose,harterj/moose,Chuban/moose,harterj/moose,permcody/moose,milljm/moose,liuwenf/moose,liuwenf/moose,milljm/moose,lindsayad/moose,idaholab/moose,yipenggao/moose,dschwen/moose,andrsd/moose,backmari/moose,permcody/moose,sapitts/moose,permcody/moose,jessecarterMOOSE/moose,YaqiWang/moose,Chuban/moose,SudiptaBiswas/moose,Chuban/moose,jessecarterMOOSE/moose,dschwen/moose,laagesen/moose,YaqiWang/moose,sapitts/moose,andrsd/moose,permcody/moose,jessecarterMOOSE/moose,YaqiWang/moose,nuclear-wizard/moose,friedmud/moose,idaholab/moose,yipenggao/moose,Chuban/moose,harterj/moose,lindsayad/moose,liuwenf/moose,lindsayad/moose,friedmud/moose,dschwen/moose,milljm/moose,yipenggao/moose,dschwen/moose,sapitts/moose,jessecarterMOOSE/moose