The crash happens because a double free in the case CREATE TABLE fails
because there is a conflicting tables on disk.
Fixed by ensuring that the double free can't happen.
The problem was that opt_sum_query() was, as part of MIN/MAX optimization,
doing read operations on constant tables that where already closed
Fixed by ensuring we don't try to read from tables that are closed.
Problem was that Create_field::create_length_to_internal_length()
calculated a different pack_length for NEWDECIMAL compared to
Field_new_decimal constructor which lead to some unused bytes
in the middle of the record, which Aria didn't like.
Problem was that the number of NULL bit's was record wrong in the
.frm file because there could be more fields marked NOT_NULL after the
number of not_null fields where recorded.
Fixed by copying test for virtual fields from prepare_create_field()
The code change, only the test, doesn't have to be merged to 10.3
as this is fixed there.
