minor symfony#53223 [Messenger] consistently use dates in UTC in Doctrine connection tests (xabbuh)

This PR was merged into the 6.3 branch.

Discussion
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[Messenger] consistently use dates in UTC in Doctrine connection tests

| Q             | A
| ------------- | ---
| Branch?       | 6.3
| Bug fix?      | no
| New feature?  | no
| Deprecations? | no
| Issues        |
| License       | MIT

related to symfony#50287 and symfony#53187

Commits
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10801e1 consistently use dates in UTC in Doctrine connection tests

Author: xabbuh

src/Symfony/Component/Messenger/Bridge/Doctrine/Tests/Transport/DoctrineIntegrationTest.php

@@ -72,9 +72,9 @@ public function testSendWithDelay()
             $stmt = $stmt->execute();
         }
 
-        $availableAt = new \DateTimeImmutable($stmt instanceof Result ? $stmt->fetchOne() : $stmt->fetchColumn());
+        $availableAt = new \DateTimeImmutable($stmt instanceof Result ? $stmt->fetchOne() : $stmt->fetchColumn(), new \DateTimeZone('UTC'));
 
-        $now = new \DateTimeImmutable('now + 60 seconds');
+        $now = new \DateTimeImmutable('now + 60 seconds', new \DateTimeZone('UTC'));
         $this->assertGreaterThan($now, $availableAt);
     }
 
@@ -91,9 +91,9 @@ public function testSendWithNegativeDelay()
         // DBAL 2 compatibility
         $result = method_exists($qb, 'executeQuery') ? $qb->executeQuery() : $qb->execute();
 
-        $availableAt = new \DateTimeImmutable($result->fetchOne());
+        $availableAt = new \DateTimeImmutable($result->fetchOne(), new \DateTimeZone('UTC'));
 
-        $now = new \DateTimeImmutable('now - 60 seconds');
+        $now = new \DateTimeImmutable('now - 60 seconds', new \DateTimeZone('UTC'));
         $this->assertLessThan($now, $availableAt);
     }
 
@@ -175,7 +175,7 @@ public function testItCountMessages()
     public function testItRetrieveTheMessageThatIsOlderThanRedeliverTimeout()
     {
         $this->connection->setup();
-        $twoHoursAgo = new \DateTimeImmutable('now -2 hours');
+        $twoHoursAgo = new \DateTimeImmutable('now -2 hours', new \DateTimeZone('UTC'));
         $this->driverConnection->insert('messenger_messages', [
             'body' => '{"message": "Hi requeued"}',
             'headers' => json_encode(['type' => DummyMessage::class]),