More cleanups and fixes

Author: nicolas-grekas

Tests/Transport/AmqpReceiverTest.php

@@ -18,9 +18,6 @@
 use Symfony\Component\Messenger\Bridge\Amqp\Transport\Connection;
 use Symfony\Component\Messenger\Envelope;
 use Symfony\Component\Messenger\Exception\TransportException;
-use Symfony\Component\Messenger\Transport\AmqpExt\AmqpReceivedStamp;
-use Symfony\Component\Messenger\Transport\AmqpExt\AmqpReceiver;
-use Symfony\Component\Messenger\Transport\AmqpExt\Connection;
 use Symfony\Component\Messenger\Transport\Serialization\Serializer;
 use Symfony\Component\Messenger\Transport\Serialization\SerializerInterface;
 use Symfony\Component\Serializer as SerializerComponent;

Tests/Transport/AmqpSenderTest.php

@@ -18,10 +18,6 @@
 use Symfony\Component\Messenger\Bridge\Amqp\Transport\Connection;
 use Symfony\Component\Messenger\Envelope;
 use Symfony\Component\Messenger\Exception\TransportException;
-use Symfony\Component\Messenger\Tests\Fixtures\DummyMessage;
-use Symfony\Component\Messenger\Transport\AmqpExt\AmqpSender;
-use Symfony\Component\Messenger\Transport\AmqpExt\AmqpStamp;
-use Symfony\Component\Messenger\Transport\AmqpExt\Connection;
 use Symfony\Component\Messenger\Transport\Serialization\SerializerInterface;
 
 /**