Add INVALID_BLOCK_ID (not currently being used).
Add INVALID_BLOCK_ID (not currently being used).

Avoid possibility of INVALID_BLOCK_ID colliding with ANY_BLOCK_ID.

Refs libmesh/libmesh#422

wgapl/moose,xy515258/moose,SudiptaBiswas/moose,friedmud/moose,katyhuff/moose,yipenggao/moose,jessecarterMOOSE/moose,roystgnr/moose,backmari/moose,mellis13/moose,andrsd/moose,kasra83/moose,jessecarterMOOSE/moose,joshua-cogliati-inl/moose,raghavaggarwal/moose,idaholab/moose,YaqiWang/moose,milljm/moose,markr622/moose,jhbradley/moose,harterj/moose,joshua-cogliati-inl/moose,waxmanr/moose,nuclear-wizard/moose,katyhuff/moose,danielru/moose,xy515258/moose,capitalaslash/moose,adamLange/moose,markr622/moose,Chuban/moose,milljm/moose,capitalaslash/moose,raghavaggarwal/moose,bwspenc/moose,liuwenf/moose,friedmud/moose,laagesen/moose,xy515258/moose,jasondhales/moose,SudiptaBiswas/moose,danielru/moose,jinmm1992/moose,apc-llc/moose,sapitts/moose,yipenggao/moose,SudiptaBiswas/moose,permcody/moose,jbair34/moose,joshua-cogliati-inl/moose,jinmm1992/moose,apc-llc/moose,dschwen/moose,jinmm1992/moose,nuclear-wizard/moose,nuclear-wizard/moose,sapitts/moose,stimpsonsg/moose,adamLange/moose,capitalaslash/moose,dschwen/moose,danielru/moose,apc-llc/moose,lindsayad/moose,waxmanr/moose,jessecarterMOOSE/moose,xy515258/moose,wgapl/moose,lindsayad/moose,stimpsonsg/moose,harterj/moose,laagesen/moose,sapitts/moose,capitalaslash/moose,jhbradley/moose,mellis13/moose,mellis13/moose,jasondhales/moose,danielru/moose,harterj/moose,Chuban/moose,nuclear-wizard/moose,dschwen/moose,Chuban/moose,liuwenf/moose,raghavaggarwal/moose,andrsd/moose,backmari/moose,jbair34/moose,permcody/moose,markr622/moose,idaholab/moose,katyhuff/moose,roystgnr/moose,permcody/moose,jasondhales/moose,jhbradley/moose,roystgnr/moose,milljm/moose,joshua-cogliati-inl/moose,milljm/moose,YaqiWang/moose,roystgnr/moose,bwspenc/moose,idaholab/moose,roystgnr/moose,jhbradley/moose,backmari/moose,laagesen/moose,wgapl/moose,jessecarterMOOSE/moose,jessecarterMOOSE/moose,yipenggao/moose,permcody/moose,backmari/moose,sapitts/moose,giopastor/moose,yipenggao/moose,andrsd/moose,jiangwen84/moose,YaqiWang/moose,markr622/moose,lindsayad/moose,jinmm1992/moose,adamLange/moose,sapitts/moose,bwspenc/moose,stimpsonsg/moose,apc-llc/moose,milljm/moose,kasra83/moose,jiangwen84/moose,dschwen/moose,andrsd/moose,liuwenf/moose,katyhuff/moose,SudiptaBiswas/moose,jasondhales/moose,stimpsonsg/moose,SudiptaBiswas/moose,mellis13/moose,dschwen/moose,idaholab/moose,roystgnr/moose,adamLange/moose,andrsd/moose,liuwenf/moose,giopastor/moose,giopastor/moose,bwspenc/moose,roystgnr/moose,bwspenc/moose,liuwenf/moose,jbair34/moose,jiangwen84/moose,YaqiWang/moose,wgapl/moose,laagesen/moose,harterj/moose,liuwenf/moose,lindsayad/moose,friedmud/moose,idaholab/moose,giopastor/moose,waxmanr/moose,kasra83/moose,waxmanr/moose,raghavaggarwal/moose,Chuban/moose,kasra83/moose,laagesen/moose,jiangwen84/moose,harterj/moose,friedmud/moose,jbair34/moose,lindsayad/moose