Merge branch '3.4' into 4.1

* 3.4:
  Think positive
  KernelInterface can return null container
  [DI] Detect circular references with ChildDefinition parent
  [VarDumper] Fix global dump function return value for PHP7
  [Ldap] Use shut up operator on connection errors at ldap_start_tls
  Implement startTest rather than startTestSuite
  [OptionsResolver] remove dead code and useless else
  [HttpFoundation] don't override StreamedResponse::setNotModified()
  Added relevent links for parsing to the phpdoc
  Add stricter checking for valid date time string
  Fix symfony/console (optional) dependency for MonologBridge
  [Form] Fix DateTimeType html5 input format

Author: nicolas-grekas

OptionsResolver.php

@@ -770,7 +770,9 @@ public function offsetGet($option)
 
                     // Don't include closures in the exception message
                     continue;
-                } elseif ($value === $allowedValue) {
+                }
+
+                if ($value === $allowedValue) {
                     $success = true;
                     break;
                 }
@@ -1041,17 +1043,4 @@ private static function isValueValidType(string $type, $value): bool
     {
         return (\function_exists($isFunction = 'is_'.$type) && $isFunction($value)) || $value instanceof $type;
     }
-
-    private function getInvalidValues(array $arrayValues, string $type): array
-    {
-        $invalidValues = array();
-
-        foreach ($arrayValues as $key => $value) {
-            if (!self::isValueValidType($type, $value)) {
-                $invalidValues[$key] = $value;
-            }
-        }
-
-        return $invalidValues;
-    }
 }