HBASE-27718 The regionStateNode only need remove once in regionOffline (#5106)

Signed-off-by: Duo Zhang <[email protected]>
(cherry picked from commit e6977a9)

Author: chaijunjie0101

hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/AssignmentManager.java

@@ -1043,8 +1043,6 @@ public void deleteTable(final TableName tableName) throws IOException {
     regionStateStore.deleteRegions(regions);
     for (int i = 0; i < regions.size(); ++i) {
       final RegionInfo regionInfo = regions.get(i);
-      // we expect the region to be offline
-      regionStates.removeFromOfflineRegions(regionInfo);
       regionStates.deleteRegion(regionInfo);
     }
   }

hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/RegionStates.java

@@ -680,11 +680,6 @@ public void addToOfflineRegions(final RegionStateNode regionNode) {
     regionOffline.put(regionNode.getRegionInfo(), regionNode);
   }
 
-  // TODO: Unused.
-  public void removeFromOfflineRegions(final RegionInfo regionInfo) {
-    regionOffline.remove(regionInfo);
-  }
-
   // ==========================================================================
   // Region FAIL_OPEN helpers
   // ==========================================================================