Issue #3166317 by longwave, anu.a_zyxware: Remove remaining references to XCache

core/includes/utility.inc

@@ -15,8 +15,7 @@
  *
  * @param $class_loader
  *   The class loader. Normally Composer's ClassLoader, as included by the
- *   front controller, but may also be decorated; e.g.,
- *   \Symfony\Component\ClassLoader\ApcClassLoader, \Symfony\Component\ClassLoader\WinCacheClassLoader, or \Symfony\Component\ClassLoader\XcacheClassLoader
+ *   front controller, but may also be decorated.
  * @param \Symfony\Component\HttpFoundation\Request $request
  *   The current request.
  *

core/misc/cspell/dictionary.txt

@@ -2053,7 +2053,6 @@ xampl
 xbap
 xbeg
 xbitmap
-xcache
 xfbml
 xhr's
 xjkm

core/rebuild.php

@@ -46,7 +46,6 @@
   $user_caches = [
     'apcu_clear_cache',
     'wincache_ucache_clear',
-    'xcache_clear_cache',
   ];
   array_map('call_user_func', array_filter($user_caches, 'is_callable'));