Check if restart is pending before trying to lock SHM

This reduces lock contention when Opcache restart is scheduled
but not yet started.

Closes GH-11805

NEWS

@@ -21,6 +21,8 @@ PHP                                                                        NEWS
 - Opcache:
   . Fixed bug GH-11715 (opcache.interned_strings_buffer either has no effect or
     opcache_get_status() / phpinfo() is wrong). (nielsdos)
+  . Avoid adding an unnecessary read-lock when loading script from shm if
+    restart is in progress. (mikhainin)
 
 - Standard:
   . Prevent int overflow on $decimals in number_format. (Marc Bennewitz)

ext/opcache/zend_file_cache.c

@@ -1786,6 +1786,7 @@ zend_persistent_script *zend_file_cache_script_load(zend_file_handle *file_handl
 
 	if (!file_cache_only &&
 	    !ZCSG(restart_in_progress) &&
+	    !ZCSG(restart_pending) &&
 		!ZSMMG(memory_exhausted) &&
 	    accelerator_shm_read_lock() == SUCCESS) {
 		/* exclusive lock */