Fix for bug #24117 "server crash on a FETCH with a cursor on a table which is not in the table cache"

Problem:
When creating a temporary field for a temporary table in create_tmp_field_from_field(), a resulting field is created as an exact copy of an original one (in Field::new_field()). However, Field_enum and Field_set contain a pointer (typelib) to memory allocated in the parent table's MEM_ROOT, which under some circumstances may be deallocated later by the time a temporary table is used.

Solution:
Override the new_field() method for Field_enum and Field_set and create a separate copy of the typelib structure in there.


include/typelib.h:
  Added copy_typelib() declaration
mysql-test/r/sp.result:
  Added a testcase for bug #24117 "server crash on a FETCH with a cursor on a table which is not in the table cache"
mysql-test/t/sp.test:
  Added a testcase for bug #24117 "server crash on a FETCH with a cursor on a table which is not in the table cache"
mysys/typelib.c:
  Added copy_typelib() definition
sql/field.cc:
  Create a copy of the internal 'typelib' structure when copying Field_enum of Field_set objects.
sql/field.h:
  Override new_field method in Field_enum (and Field_set) to copy the typelib structure.