NO_AUTO_VALUE_ON_ZERO mode.

In the NO_AUTO_VALUE_ON_ZERO mode the table->auto_increment_field_not_null
variable is used to indicate that a non-NULL value was specified by the user
for an auto_increment column. When an INSERT .. ON DUPLICATE updates the
auto_increment field this variable is set to true and stays unchanged for the
next insert operation. This makes the next inserted row sometimes wrongly have
0 as the value of the auto_increment field.

Now the fill_record() function resets the table->auto_increment_field_not_null
variable before filling the record.
The table->auto_increment_field_not_null variable is also reset by the
open_table() function for a case if we missed some auto_increment_field_not_null
handling bug.
Now the table->auto_increment_field_not_null is reset at the end of the
mysql_load() function.

Reset the table->auto_increment_field_not_null variable after each
write_row() call in the copy_data_between_tables() function.