Compatible with aliyun redis instance

Some cloud provider's redis instance is just compatible in common use command, but not some special command.
Just like aliyun redis instance, doc: https://help.aliyun.com/document_detail/26342.html
It based on redis protocol, but not really like the redis I know...

I found that `$host->info('Memory')` will return false/null sometime, so and more safe check will be better for those special redis server.

src/Symfony/Component/Cache/Adapter/RedisTagAwareAdapter.php

@@ -292,13 +292,13 @@ private function getRedisEvictionPolicy(): string
         foreach ($hosts as $host) {
             $info = $host->info('Memory');
 
-            if ($info instanceof ErrorInterface) {
+            if ($info === false || $info === null || $info instanceof ErrorInterface) {
                 continue;
             }
 
             $info = $info['Memory'] ?? $info;
 
-            return $this->redisEvictionPolicy = $info['maxmemory_policy'];
+            return $this->redisEvictionPolicy = $info['maxmemory_policy'] ?? '';
         }
 
         return $this->redisEvictionPolicy = '';