We hit an ASSERT in debug mode in optimize_aggregated_query
when optimizing a MAX/MIN aggregate in an IN subquery iff the aggregate
references an outer field AND the field is part of a row in
a single row in-memory table. In this case, the row will have been read
and the table closed again before the optimization of the subquery.

The ASSERT that failed didn't anticipate this case (that the table
referenced could be a constant table). This was not an issue before
WL11935, because earlier, such a field would be marked as an outer
reference.  WL11935 causes us to call update_used_tables again after
the in-memory table row has been read causing OUTER_REF_TABLE_BIT to
be no longer set. This gives a changed code path in
optimize_aggregated_query.

Change-Id: I115a0a10699c75985dc841b82cc133841af30946