Merge branch '3.4'

* 3.4:
  [DI] use assertStringEqualsFile when possible
  [VarDumper] Adapt to php 7.2 changes
  [DI] Fix using private services in expressions
  [Form][TwigBridge] Don't render _method in form_rest() for a child form
  [Form] Static call TimezoneType::getTimezones
  Removed references for non existent validator constraints
  Suggest using quotes instead of Yaml::PARSE_KEYS_AS_STRINGS
  [DI] Fix test
  [Cache] Handle unserialization failures for Memcached
  Remove unused prop + added @deprecated
  Remove unused mocks/vars
  feature #22317 [Console] Make SymfonyQuestionHelper::ask optional by default (ro0NL)
  [DoctrineBridge][PropertyInfo] Added support for Doctrine Embeddables
  [Validator] Fix IbanValidator for ukrainian IBANs
  Router: allow HEAD method to be defined first
  [WebProfilerBundle] Display trace and context in the logger profiler
  Fixing a bug where if a core class was autowired, autowiring tried to autowire optional args as if they were required

Author: nicolas-grekas

Extension/Core/Type/TimezoneType.php

@@ -63,7 +63,7 @@ public function loadChoiceList($value = null)
             return $this->choiceList;
         }
 
-        return $this->choiceList = new ArrayChoiceList($this->getTimezones(), $value);
+        return $this->choiceList = new ArrayChoiceList(self::getTimezones(), $value);
     }
 
     /**

Extension/Validator/ValidatorTypeGuesser.php

@@ -151,8 +151,6 @@ public function guessTypeForConstraint(Constraint $constraint)
             case 'Symfony\Component\Validator\Constraints\Count':
                 return new TypeGuess('Symfony\Component\Form\Extension\Core\Type\CollectionType', array(), Guess::LOW_CONFIDENCE);
 
-            case 'Symfony\Component\Validator\Constraints\True':
-            case 'Symfony\Component\Validator\Constraints\False':
             case 'Symfony\Component\Validator\Constraints\IsTrue':
             case 'Symfony\Component\Validator\Constraints\IsFalse':
                 return new TypeGuess('Symfony\Component\Form\Extension\Core\Type\CheckboxType', array(), Guess::MEDIUM_CONFIDENCE);
@@ -171,7 +169,6 @@ public function guessRequiredForConstraint(Constraint $constraint)
         switch (get_class($constraint)) {
             case 'Symfony\Component\Validator\Constraints\NotNull':
             case 'Symfony\Component\Validator\Constraints\NotBlank':
-            case 'Symfony\Component\Validator\Constraints\True':
             case 'Symfony\Component\Validator\Constraints\IsTrue':
                 return new ValueGuess(true, Guess::HIGH_CONFIDENCE);
         }