HBASE-27282 CME in AuthManager causes region server crash (#4684)

Signed-off-by: Duo Zhang <zhangduo@apache.org>
(cherry picked from commit d664162)

Author: chaijunjie0101

hbase-server/src/main/java/org/apache/hadoop/hbase/security/access/AuthManager.java

@@ -19,7 +19,6 @@
 
 import java.io.IOException;
 import java.util.HashMap;
-import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -66,7 +65,7 @@ private static class PermissionCache<T extends Permission> {
 
     void put(String name, T perm) {
       synchronized (mutex) {
-        Set<T> perms = cache.getOrDefault(name, new HashSet<>());
+        Set<T> perms = cache.getOrDefault(name, ConcurrentHashMap.newKeySet());
         perms.add(perm);
         cache.put(name, perms);
       }