v.21.9Backward Incompatible Changes

Fix Bad Cast Issue with Column Aliases in Sophisticated Queries

Fix the issue that in case of some sophisticated query with column aliases identical to the names of expressions, bad cast may happen. This fixes #25447. This fixes #26914. This fix may introduce backward incompatibility: if there are different expressions with identical names, exception will be thrown. It may break some rare cases when enable_optimize_predicate_expression is set. #26639 (alexey-milovidov).