Document removal of opcache.fast_shutdown

[ci skip]

Author: nikic

Diff for: UPGRADING

@@ -356,6 +356,11 @@ See also: https://wiki.php.net/rfc/deprecations_php_7_2
 - realpath_cache_size
   . Set to 4096k by default
 
+- opcache.fast_shutdown
+  . This INI directive has been removed. A variant of the fast_shutdown
+    process has been integrated into PHP core and is always enabled for
+    production builds if possible.
+
 ========================================
 12. Windows Support
 ========================================

Diff for: php.ini-development

@@ -1797,10 +1797,6 @@ ldap.max_links = -1
 ; size of the optimized code.
 ;opcache.save_comments=1
 
-; If enabled, a fast shutdown sequence is used for the accelerated code
-; Depending on the used Memory Manager this may cause some incompatibilities.
-;opcache.fast_shutdown=0
-
 ; Allow file existence override (file_exists, etc.) performance feature.
 ;opcache.enable_file_override=0
 

Diff for: php.ini-production

@@ -1804,10 +1804,6 @@ ldap.max_links = -1
 ; size of the optimized code.
 ;opcache.save_comments=1
 
-; If enabled, a fast shutdown sequence is used for the accelerated code
-; Depending on the used Memory Manager this may cause some incompatibilities.
-;opcache.fast_shutdown=0
-
 ; Allow file existence override (file_exists, etc.) performance feature.
 ;opcache.enable_file_override=0