innodb-test: Allow Innodb_buffer_pool_pages_total to be 511 or 512.

The size of the buffer pool can be one page smaller than the requested
size when os_mem_alloc_large() returns something that is not
aligned by UNIV_PAGE_SIZE.  This test may still fail on systems with
a big os_large_page_size.

mysql-test/innodb.test

@@ -1311,6 +1311,7 @@ drop table t1;
 
 # Test for testable InnoDB status variables. This test
 # uses previous ones(pages_created, rows_deleted, ...).
+--replace_result 512 511
 show status like "Innodb_buffer_pool_pages_total";
 show status like "Innodb_page_size";
 show status like "Innodb_rows_deleted";