Rework to resolve ambigious grammer: conflict in join expression
  handling of parentheses for nested joins and derived tables.
  Tests included of failing statements
Optimize item construction for AND/OR logical expressions


mysql-test/r/select.result:
  Bug#8670
    Tests for failing expressions
mysql-test/t/select.test:
  Bug#8670
    Tests for failing expressions
sql/sql_parse.cc:
  Bug#8670
    method st_select_lex::end_nested_join() returns NULL when
    there are no elements in the join.
sql/sql_yacc.yy:
  Optimize construction for Item_cond_or and Item_cond_and
    Reduces object count in case of complex expressions.
  Bug#8670
    Solve ambigious grammar.
    Fix handling of parentheses in join expressions to
    correct handling of nested joins and derived tables.