Changed resolving of the coalesced column

Changed resolving of the coalesced column from OUTER JOIN ... USING clause to be more consistent: previously, when selecting both the USING column and qualified columns (a, t1.a, t2.a) in a OUTER JOIN, the USING column would incorrectly be resolved to t1.a, showing 0/NULL for rows from the right table with no left match. Now identifiers from USING clause are always resolved to the coalesced column, while qualified identifiers resolve to the non-coalesced columns, regardless of which other identifiers are present in the query. For example: ```sql SELECT a, t1.a, t2.a FROM (SELECT 1 as a WHERE 0) t1 FULL JOIN (SELECT 2 as a) t2 USING (a) -- Before: a=0, t1.a=0, t2.a=2 (incorrect - 'a' resolved to t1.a) -- After: a=2, t1.a=0, t2.a=2 (correct - 'a' is coalesced). #80848 (Vladimir Cherkasov).