BUG#25330449 ASSERT SIZE==SPACE->SIZE DURING BUF_READ_AHEAD_RANDOM

Problem:

During read head, wrong page size is used to calcuate the tablespace size.

Fix:

Use physical page size to calculate tablespace size

Reveiwed-By: Satya Bodapati
RB: 14993

storage/innobase/buf/buf0rea.cc

 /*****************************************************************************
 
-Copyright (c) 1995, 2016, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 1995, 2017, Oracle and/or its affiliates. All Rights Reserved.
 Copyright (c) 2015, 2016 MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
@@ -301,10 +301,10 @@ buf_read_ahead_random(
 			     node = UT_LIST_GET_NEXT(chain, node)) {
 
 				size += os_file_get_size(node->handle)
-					/ page_size.logical();
+					/ page_size.physical();
 			}
 
-			ut_ad(size==space->size);
+			ut_ad(size == space->size);
 		}
 #endif /* UNIV_DEBUG */