minor #19624 [Bridge/Twig] Simplify dumping snippet (nicolas-grekas)

This PR was merged into the 3.2-dev branch.

Discussion
----------

[Bridge/Twig] Simplify dumping snippet

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | needs #19623
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

Commits
-------

ef7122e [Bridge/Twig] Simplify dumping snippet

src/Symfony/Bridge/Twig/Extension/DumpExtension.php

@@ -69,16 +69,11 @@ public function dump(\Twig_Environment $env, $context)
         }
 
         $dump = fopen('php://memory', 'r+b');
-        $prevOutput = $this->dumper->setOutput($dump);
 
         foreach ($vars as $value) {
-            $this->dumper->dump($this->cloner->cloneVar($value));
+            $this->dumper->dump($this->cloner->cloneVar($value), $dump);
         }
 
-        $this->dumper->setOutput($prevOutput);
-
-        rewind($dump);
-
-        return stream_get_contents($dump);
+        return stream_get_contents($dump, -1, 0);
     }
 }

src/Symfony/Bridge/Twig/composer.json

@@ -33,7 +33,7 @@
         "symfony/security-acl": "~2.8|~3.0",
         "symfony/stopwatch": "~2.8|~3.0",
         "symfony/console": "~2.8|~3.0",
-        "symfony/var-dumper": "~2.8.9|~3.0.9|~3.1.3|~3.2",
+        "symfony/var-dumper": "~2.8.10|~3.1.4|~3.2",
         "symfony/expression-language": "~2.8|~3.0"
     },
     "suggest": {