statements
Currently the optimizer evaluates loose index scan only for top-level SELECT
statements
Extend loose index scan applicability by :
 - Test the applicability of loose scan for each sub-select, instead of the
   whole query. This change enables loose index scan for sub-queries.
 - allow non-select statements with SELECT parts (like, e.g. 
   CREATE TABLE .. SELECT ...) to use loose index scan.


mysql-test/r/group_min_max.result:
  Bug#24156: Loose index scan not used with CREATE TABLE ...SELECT and similar
             statements
   - test case
mysql-test/t/group_min_max.test:
  Bug#24156: Loose index scan not used with CREATE TABLE ...SELECT and similar
             statements
   - test case
sql/opt_range.cc:
  Bug#24156: Loose index scan not used with CREATE TABLE ...SELECT and similar
             statements
   - loose index scan will be tried over the current subselect 
     (lex->current_select) instead of the whole query (lex->select_lex).
   - allow non-select statements with SELECT parts (like, e.g. 
     CREATE TABLE .. SELECT ...) to use loose index scan.