The problem is a shift operation that is not 64-bit safe.
The consequence is that used tables information for a join with 32 tables
or more will be incorrect.

Fixed by adding a type cast in Item_sum::update_used_tables().

Also used the opportunity to fix some other potential bugs by adding an
explicit type-cast to an integer in a left-shift operation.
Some of them were quite harmless, but was fixed in order to get the same
signed-ness as the other operand of the operation it was used in.

sql/item_cmpfunc.cc
  Adjusted signed-ness for some integers in left-shift.

sql/item_subselect.cc
  Added type-cast to nesting_map (which is a 32/64 bit type, so
  potential bug for deeply nested queries).

sql/item_sum.cc
  Added type-cast to nesting_map (32/64-bit type) and table_map
  (64-bit type).

sql/opt_range.cc
  Added type-cast to ulonglong (which is a 64-bit type).

sql/sql_base.cc
  Added type-cast to nesting_map (which is a 32/64-bit type).

sql/sql_select.cc
  Added type-cast to nesting_map (32/64-bit type) and key_part_map
  (64-bit type).

sql/strfunc.cc
  Changed type-cast from longlong to ulonglong, to preserve signed-ness.