minor #45045 [VarDumper] fix tests (nicolas-grekas)

This PR was merged into the 5.3 branch.

Discussion
----------

[VarDumper] fix tests

| Q             | A
| ------------- | ---
| Branch?       | 5.3
| Bug fix?      | no
| New feature?  | no
| Deprecations? | no
| Tickets       | no
| License       | MIT
| Doc PR        | -

Commits
-------

7578cfa4a8 [VarDumper] fix tests

src/Symfony/Component/VarDumper/Tests/Caster/RdKafkaCasterTest.php

@@ -77,9 +77,7 @@ EODUMP;
 
         $expectedDump = <<<EODUMP
 RdKafka\Producer {
-  -error_cb: null
-  -dr_cb: null
-  out_q_len: %d
+%Aout_q_len: %d
   orig_broker_id: 1001
   orig_broker_name: "$this->broker/1001"
   brokers: RdKafka\Metadata\Collection {
@@ -146,10 +144,7 @@ EODUMP;
 
         $expectedDump = <<<EODUMP
 RdKafka\KafkaConsumer {
-  -error_cb: null
-  -rebalance_cb: null
-  -dr_msg_cb: null
-  subscription: array:1 [
+%Asubscription: array:1 [
     0 => "test-topic"
   ]
   assignment: []