Merge branch '2.6' into 2.7

* 2.6: (24 commits)
  [Form] fixed a maxlength overring on a guessing
  [Debug] Show only unique class candidates
  [SecurityBundle] Firewall providers building - code cleaning
  [Filesystem] symlink use RealPath instead LinkTarget
  [DependencyInjection] Remove duplicate  declaration in PhpDumper
  terminals are not interactive on Travis
  Revert "[DependencyInjection] backport perf optim"
  [WebProfiler] Tweaked ajax requests toolbar css reset
  [WebProfilerBundle] replaced pattern to path attribute in routes definitions.
  fix phpdoc's alignment
  Fix missing addExpressionLanguageProvider (used by service container to add expression providers)
  Fixed the AuthenticationProviderInterface alignment
  Fixed the proxy-manager version constraint
  Fix missing space in label_attr
  fix DumpDataCollectorTest after CS changes
  avoid risky tests
  Fixed typo in SecurityContext PHPDoc
  [FrameworkBundle][Template name] avoid  error message for the shortcut notation.
  [DependencyInjection] perf optim: call dirname() at most 5x
  [DependencyInjection] backport perf optim
  ...

Author: nicolas-grekas

OptionsResolver.php

@@ -833,7 +833,7 @@ public function offsetGet($option)
             // BEGIN
             $this->calling[$option] = true;
             foreach ($this->lazy[$option] as $closure) {
-                $value = call_user_func($closure, $this, $value);
+                $value = $closure($this, $value);
             }
             unset($this->calling[$option]);
             // END
@@ -929,7 +929,7 @@ public function offsetGet($option)
             // dependency
             // BEGIN
             $this->calling[$option] = true;
-            $value = call_user_func($normalizer, $this, $value);
+            $value = $normalizer($this, $value);
             unset($this->calling[$option]);
             // END
         }