HBASE-23193 ConnectionImplementation.isTableAvailable can not deal with meta table on branch-2.x

Author: Apache9

hbase-client/src/main/java/org/apache/hadoop/hbase/client/ConnectionImplementation.java

@@ -639,6 +639,10 @@ public boolean isTableAvailable(final TableName tableName, @Nullable final byte[
         LOG.debug("Table {} not enabled", tableName);
         return false;
       }
+      if (TableName.isMetaTableName(tableName)) {
+        // meta table is always available
+        return true;
+      }
       List<Pair<RegionInfo, ServerName>> locations =
         MetaTableAccessor.getTableRegionsAndLocations(this, tableName, true);