Merge branch '6.1' into 6.2

* 6.1:
  [HttpKernel] Fix test sensitivity on xdebug.file_link_format
  [HttpKernel] Fix non-scalar check in surrogate fragment renderer
  [HtmlSanitizer] Allow null for sanitizer option `allowed_link_hosts` and `allowed_media_hosts`
  [Serializer] Fix wrong needsNormalization in TraceableEncoder
  [Debug][ErrorHandler] fix operator precedence
  [Cache] Ensured that redis adapter can use multiple redis sentinel hosts
  [DoctrineBridge] fix tests
  [Security] Allow redirect after login to absolute URLs

Author: nicolas-grekas

ErrorHandler.php

@@ -359,7 +359,7 @@ public function screamAt(int $levels, bool $replace = false): int
      */
     private function reRegister(int $prev): void
     {
-        if ($prev !== $this->thrownErrors | $this->loggedErrors) {
+        if ($prev !== ($this->thrownErrors | $this->loggedErrors)) {
             $handler = set_error_handler('is_int');
             $handler = \is_array($handler) ? $handler[0] : null;
             restore_error_handler();