Don't call Symfony ProcessUtils::escapeArgument

src/Composer/Util/ProcessExecutor.php

@@ -131,15 +131,11 @@ class ProcessExecutor
      */
     public static function escape($argument)
     {
-        if (method_exists('Symfony\Component\Process\ProcessUtils', 'escapeArgument')) {
-            return ProcessUtils::escapeArgument($argument);
-        }
-
         return self::escapeArgument($argument);
     }
 
     /**
-     * Copy of ProcessUtils::escapeArgument() that is removed in Symfony 4.
+     * Copy of ProcessUtils::escapeArgument() that is deprecated in Symfony 3.3 and removed in Symfony 4.
      *
      * @param string $argument
      *