Merge branch '4.4'

* 4.4:
  [PhpUnitBridge] fix internal annotation
  [Mime] added AbstractPart::asDebugString()
  [Mailer] added a name to the transport
  [Mailer] added missing entry in the CHANGELOG
  [FrameworkBundle] add config translator cache_dir
  [Yaml] Add flag to dump NULL as ~

Author: nicolas-grekas

Legacy/PolyfillAssertTrait.php

@@ -17,7 +17,7 @@
 use PHPUnit\Framework\Constraint\TraversableContains;
 
 /**
- * @internal
+ * This trait is @internal
  */
 trait PolyfillAssertTrait
 {

Legacy/PolyfillTestCaseTrait.php

@@ -15,7 +15,7 @@
 use PHPUnit\Framework\TestCase;
 
 /**
- * @internal
+ * This trait is @internal
  */
 trait PolyfillTestCaseTrait
 {

bin/simple-phpunit.php

@@ -156,12 +156,6 @@
     $alteredCode = preg_replace('/abstract class (?:Assert|PHPUnit_Framework_Assert)[^\{]+\{/', '$0 '.PHP_EOL."    use \Symfony\Bridge\PhpUnit\Legacy\PolyfillAssertTrait;", $alteredCode, 1);
     file_put_contents($alteredFile, $alteredCode);
 
-    // remove internal annotation from polyfill
-    foreach (array('PolyfillTestCaseTrait', 'PolyfillAssertTrait') as $polyfill) {
-        $traitFile = "./vendor/symfony/phpunit-bridge/Legacy/$polyfill.php";
-        file_put_contents($traitFile, str_replace(' * @internal', '', file_get_contents($traitFile)));
-    }
-
     file_put_contents('phpunit', <<<'EOPHP'
 <?php