[Maria-developers] MDEV-7950 Item_func::type() takes 0.26% in OLTP RO

Hello Sergey, Please review the next step for MDEV-7950. It does the following: - Adds specific implementations of virtual method get_mm_tree() into Item_func_like, Item_bool_rowready_func2, Item_func_spatial_rel - Gets rid of two virtual calls: select_optimize() and have_rev_func(). - Removes virtual methods Item_func::select_optimize(), Item_func::have_rev_func(), as well as enum Item_func::optimize_type, because they are not needed any more. Thanks.