Merge branch '5.1' into 5.2

* 5.1:
  Dont allow unserializing classes with a destructor
  Dont allow unserializing classes with a destructor - 4.4
  [Cache] fix possible collision when writing tmp file in filesystem adapter
  a colon followed by spaces exclusively separates mapping keys and values
  Contracts: Remove ellipsis
  fix handling float-like key attribute values
  Fix missing BCC recipients in SES bridge
  Dont allow unserializing classes with a destructor - 5.1

Author: nicolas-grekas

Tests/Functional/app/AppKernel.php

@@ -89,6 +89,12 @@ public function __sleep(): array
 
     public function __wakeup()
     {
+        foreach ($this as $k => $v) {
+            if (\is_object($v)) {
+                throw new \BadMethodCallException('Cannot unserialize '.__CLASS__);
+            }
+        }
+
         $this->__construct($this->varDir, $this->testCase, $this->rootConfig, $this->environment, $this->debug);
     }