Merge branch '3.2' into 3.3

* 3.2:
  Fix optional cache warmers are always instantiated whereas they should be lazy-loaded
  add some \ on PHP_VERSION_ID for 2.8
  [PropertyInfo][DoctrineBridge] The bigint Doctrine's type must be converted to string

Author: nicolas-grekas

Config/AutowireServiceResource.php

@@ -65,7 +65,7 @@ public function serialize()
 
     public function unserialize($serialized)
     {
-        if (PHP_VERSION_ID >= 70000) {
+        if (\PHP_VERSION_ID >= 70000) {
             list($this->class, $this->filePath, $this->autowiringMetadata) = unserialize($serialized, array('allowed_classes' => false));
         } else {
             list($this->class, $this->filePath, $this->autowiringMetadata) = unserialize($serialized);