Problem: creating a partitioned table during name resolution for the 
partition function we search for column names in all parts of the
CREATE TABLE query. It is superfluous (and wrong) sometimes.

Fix: launch name resolution for the partition function against
the table we're creating.


mysql-test/r/partition.result:
  Fix for bug #29444: crash with partition refering to table in create-select
    - test result.
mysql-test/t/partition.test:
  Fix for bug #29444: crash with partition refering to table in create-select
    - test result.
sql/item.cc:
  Fix for bug #29444: crash with partition refering to table in create-select
    - LEX::use_only_table_context introduced, which is used in the 
      Item_field::fix_fields() to resolve names only against
      context->first_name_resolution_table/last_name_resolution_table.
sql/sql_lex.cc:
  Fix for bug #29444: crash with partition refering to table in create-select
    - LEX::use_only_table_context introduced, which is used in the 
      Item_field::fix_fields() to resolve names only against
      context->first_name_resolution_table/last_name_resolution_table.
sql/sql_lex.h:
  Fix for bug #29444: crash with partition refering to table in create-select
    - LEX::use_only_table_context introduced, which is used in the 
      Item_field::fix_fields() to resolve names only against
      context->first_name_resolution_table/last_name_resolution_table.
sql/sql_partition.cc:
  Fix for bug #29444: crash with partition refering to table in create-select
    - set the lex->use_only_table_context before the func_expr->fix_fields()
      call to ensure we're resolving names against the table we're creating;
      then restore it back after the call.