minor #24863 [Bridge\Twig] Lazy-load deps (nicolas-grekas)

This PR was merged into the 3.4 branch.

Discussion
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[Bridge\Twig] Lazy-load deps

| Q             | A
| ------------- | ---
| Branch?       | 3.4
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

Spotted while benching a HelloWorld and comparing v3.3 to v4.0.
At this micro-bench level, even registering one more twig extension makes a difference (here, it's `TranslationExtension`, after #24358)

Commits
-------

3fc766f [Bridge\Twig] Lazy-load deps

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

@@ -32,7 +32,7 @@ class DumpExtension extends AbstractExtension
     public function __construct(ClonerInterface $cloner, HtmlDumper $dumper = null)
     {
         $this->cloner = $cloner;
-        $this->dumper = $dumper ?: new HtmlDumper();
+        $this->dumper = $dumper;
     }
 
     public function getFunctions()
@@ -73,6 +73,7 @@ public function dump(Environment $env, $context)
         }
 
         $dump = fopen('php://memory', 'r+b');
+        $this->dumper = $this->dumper ?: new HtmlDumper();
         $this->dumper->setCharset($env->getCharset());
 
         foreach ($vars as $value) {

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

@@ -34,10 +34,6 @@ class TranslationExtension extends AbstractExtension
 
     public function __construct(TranslatorInterface $translator = null, NodeVisitorInterface $translationNodeVisitor = null)
     {
-        if (!$translationNodeVisitor) {
-            $translationNodeVisitor = new TranslationNodeVisitor();
-        }
-
         $this->translator = $translator;
         $this->translationNodeVisitor = $translationNodeVisitor;
     }
@@ -84,12 +80,12 @@ public function getTokenParsers()
      */
     public function getNodeVisitors()
     {
-        return array($this->translationNodeVisitor, new TranslationDefaultDomainNodeVisitor());
+        return array($this->getTranslationNodeVisitor(), new TranslationDefaultDomainNodeVisitor());
     }
 
     public function getTranslationNodeVisitor()
     {
-        return $this->translationNodeVisitor;
+        return $this->translationNodeVisitor ?: $this->translationNodeVisitor = new TranslationNodeVisitor();
     }
 
     public function trans($message, array $arguments = array(), $domain = null, $locale = null)