Merge branch '3.3' into 3.4

* 3.3: (21 commits)
  [appveyor] disable memory limit on composer up
  Remove some unused variables and properties
  Remove some unused variables, properties and methods
  fix some edge cases with indented blocks
  [ExpressionLanguage] Fix parse error on 5.3
  [HttpKernel] remove noisy frame in controller stack traces
  [DI] Fix circular-aliases message
  [ExpressionLanguage] throw an SyntaxError instead of letting a undefined index notice
  Prevent a loop in aliases within the `findDefinition` method
  Fix php doc in Table class
  bumped Symfony version to 3.3.15
  updated VERSION for 3.3.14
  updated CHANGELOG for 3.3.14
  bumped Symfony version to 2.8.33
  updated VERSION for 2.8.32
  updated CHANGELOG for 2.8.32
  bumped Symfony version to 2.7.40
  updated VERSION for 2.7.39
  update CONTRIBUTORS for 2.7.39
  updated CHANGELOG for 2.7.39
  ...

Author: nicolas-grekas

Parser/TokenStream.php

@@ -31,11 +31,6 @@ class TokenStream
      */
     private $tokens = array();
 
-    /**
-     * @var bool
-     */
-    private $frozen = false;
-
     /**
      * @var Token[]
      */
@@ -49,7 +44,7 @@ class TokenStream
     /**
      * @var Token|null
      */
-    private $peeked = null;
+    private $peeked;
 
     /**
      * @var bool
@@ -75,8 +70,6 @@ public function push(Token $token)
      */
     public function freeze()
     {
-        $this->frozen = true;
-
         return $this;
     }