MDEV-18144: ANALYZE for statement support for PK filters

ANALYZE and ANALYZE FORMAT=JSON structures are changed in the way that they
show additional information when rowid filter is used:

- r_selectivity_pct - the observed filter selectivity
- r_buffer_size - the size of the rowid filter container buffer
- r_filling_time_ms - how long it took to fill rowid filter container

New class Rowid_filter_tracker was added. This class is needed to collect data
about how rowid filter is executed.

sql/handler.h

@@ -3014,6 +3014,7 @@ private:
   Exec_time_tracker *tracker;
 public:
   void set_time_tracker(Exec_time_tracker *tracker_arg) { tracker=tracker_arg;}
+  Exec_time_tracker *get_time_tracker() { return tracker; }
 
   Item *pushed_idx_cond;
   uint pushed_idx_cond_keyno;  /* The index which the above condition is for */