Problem was that dict_sys->size tries to maintain used memory
occupied by the data dictionary table and index objects.
However at least on table objects table->heap size can increase
between when table object is inserted to dict_sys and when
it is removed from dict_sys causing inconsistency on amount
of memory added to and removed from dict_sys->size variable.

Removed unnecessary dict_sys:size variable as it is really
used only for status output.

Introduced dict_sys_get_size function to calculate memory
occupied by the data dictionary table and index objects
that is then used on show engine innodb output.

dict_table_add_to_cache(),
dict_table_rename_in_cache(),
dict_table_remove_from_cache_low(),
dict_index_remove_from_cache_low(),
	Remove size calculation.

srv_printf_innodb_monitor(): Use dict_sys_get_size function to
get dictionary memory allocated.

xtradb_internal_hash_tables_fill_table(): Use dict_sys_get_size
function to get dictionary memory allocated.