when renaming tables

Allocate the table name using ut_malloc() instead of table->heap because
the latter cannot be freed.

Adjust dict_sys->size calculations all over the code.

Change dict_table_t::name from const char* to char* because we need to
ut_malloc()/ut_free() it.

Reviewed by:	Inaam, Marko, Heikki (rb://384)
Approved by:	Heikki (rb://384)