HBASE-25854 Remove redundant AM in-memory state changes in CatalogJanitor

In CatalogJanitor we schedule GCRegionProcedure to clean up both
filesystem and in-memory state after a split, and
GCMultipleMergedRegionsProcedure to do the same for merges. Both of these
procedures clean up in-memory state, but CatalogJanitor also does this
redundantly just after scheduling the procedures. The cleanup should be
done in only one place. Presumably we are using the procedures to do it in
a principled way. Remove the redundancy in CatalogJanitor and fix any
follow on issues, like test failures.

Author: apurtell

hbase-server/src/main/java/org/apache/hadoop/hbase/master/janitor/CatalogJanitor.java

@@ -254,12 +254,6 @@ private boolean cleanMergeRegion(final RegionInfo mergedRegion, List<RegionInfo>
       ProcedureExecutor<MasterProcedureEnv> pe = this.services.getMasterProcedureExecutor();
       pe.submitProcedure(
         new GCMultipleMergedRegionsProcedure(pe.getEnvironment(), mergedRegion, parents));
-      for (RegionInfo ri : parents) {
-        // The above scheduled GCMultipleMergedRegionsProcedure does the below.
-        // Do we need this?
-        this.services.getAssignmentManager().getRegionStates().deleteRegion(ri);
-        this.services.getServerManager().removeRegion(ri);
-      }
       return true;
     }
     return false;
@@ -318,9 +312,6 @@ static boolean cleanParent(MasterServices services, RegionInfo parent, Result ro
         daughterA + ", " + daughterB + " -- no longer hold references");
       ProcedureExecutor<MasterProcedureEnv> pe = services.getMasterProcedureExecutor();
       pe.submitProcedure(new GCRegionProcedure(pe.getEnvironment(), parent));
-      // Remove from in-memory states
-      services.getAssignmentManager().getRegionStates().deleteRegion(parent);
-      services.getServerManager().removeRegion(parent);
       return true;
     }
     return false;