Merge branch '3.4' into 4.2

* 3.4:
  [WebProfilerBundle] fix FC with HttpFoundation v5
  [Form] test case is not legacy
  Fix reporting unsilenced deprecations from insulated tests
  Added FormInterface to @return Form::getClickedButton docblock

Author: nicolas-grekas

src/Symfony/Bridge/PhpUnit/Legacy/SymfonyTestsListenerTrait.php

@@ -284,7 +284,8 @@ public function endTest($test, $time)
             foreach ($deprecations ? unserialize($deprecations) : array() as $deprecation) {
                 $error = serialize(array('deprecation' => $deprecation[1], 'class' => $className, 'method' => $test->getName(false), 'triggering_file' => isset($deprecation[2]) ? $deprecation[2] : null));
                 if ($deprecation[0]) {
-                    @trigger_error($error, E_USER_DEPRECATED);
+                    // unsilenced on purpose
+                    trigger_error($error, E_USER_DEPRECATED);
                 } else {
                     @trigger_error($error, E_USER_DEPRECATED);
                 }

src/Symfony/Component/BrowserKit/Client.php

@@ -457,7 +457,8 @@ protected function doRequestInProcess($request)
             unlink($deprecationsFile);
             foreach ($deprecations ? unserialize($deprecations) : [] as $deprecation) {
                 if ($deprecation[0]) {
-                    @trigger_error($deprecation[1], E_USER_DEPRECATED);
+                    // unsilenced on purpose
+                    trigger_error($deprecation[1], E_USER_DEPRECATED);
                 } else {
                     @trigger_error($deprecation[1], E_USER_DEPRECATED);
                 }

src/Symfony/Component/Form/Form.php

@@ -89,7 +89,7 @@ class Form implements \IteratorAggregate, FormInterface, ClearableErrorsInterfac
     private $submitted = false;
 
     /**
-     * @var ClickableInterface|null The button that was used to submit the form
+     * @var FormInterface|ClickableInterface|null The button that was used to submit the form
      */
     private $clickedButton;
 
@@ -747,7 +747,7 @@ public function isValid()
     /**
      * Returns the button that was used to submit the form.
      *
-     * @return ClickableInterface|null
+     * @return FormInterface|ClickableInterface|null
      */
     public function getClickedButton()
     {

src/Symfony/Component/Form/Tests/Extension/Core/Type/ChoiceTypeTest.php

@@ -725,10 +725,7 @@ public function testSubmitMultipleChoiceExpandedWithEmptyDataAndInitialData()
         $this->assertSame(['test'], $form->getData());
     }
 
-    /**
-     * @group legacy
-     */
-    public function testLegacyNullChoices()
+    public function testNullChoices()
     {
         $form = $this->factory->create(static::TESTED_TYPE, null, [
             'multiple' => false,