[SPARK-16839][SQL] Simplify Struct creation code path

## What changes were proposed in this pull request?

Simplify struct creation, especially the aspect of `CleanupAliases` which missed some aliases when handling trees created by `CreateStruct`.

This PR includes:

1. A failing test (create struct with nested aliases, some of the aliases survive `CleanupAliases`).
2. A fix that transforms `CreateStruct` into a `CreateNamedStruct` constructor, effectively eliminating `CreateStruct` from all expression trees.
3. A `NamePlaceHolder` used by `CreateStruct` when column names cannot be extracted from unresolved `NamedExpression`.
4. A new Analyzer rule that resolves `NamePlaceHolder` into a string literal once the `NamedExpression` is resolved.
5. `CleanupAliases` code was simplified as it no longer has to deal with `CreateStruct`'s top level columns.

## How was this patch tested?
Running all tests-suits in package org.apache.spark.sql, especially including the analysis suite, making sure added test initially fails, after applying suggested fix rerun the entire analysis package successfully.

Modified few tests that expected `CreateStruct` which is now transformed into `CreateNamedStruct`.

Author: eyal farago <eyal farago>
Author: Herman van Hovell <hvanhovell@databricks.com>
Author: eyal farago <eyal.farago@gmail.com>
Author: Eyal Farago <eyal.farago@actimize.com>
Author: Hyukjin Kwon <gurwls223@gmail.com>
Author: eyalfa <eyal.farago@gmail.com>

Closes #15718 from hvanhovell/SPARK-16839-2.

1 files changed, 1 insertions, 1 deletions

diff --git a/sql/hive/src/test/resources/sqlgen/subquery_in_having_2.sql b/sql/hive/src/test/resources/sqlgen/subquery_in_having_2.sql
index de0116a4dc..cdda29af50 100644
--- a/sql/hive/src/test/resources/sqlgen/subquery_in_having_2.sql
+++ b/sql/hive/src/test/resources/sqlgen/subquery_in_having_2.sql
@@ -7,4 +7,4 @@ having b.key in (select a.key
                  where a.value > 'val_9' and a.value = min(b.value))
 order by b.key
 --------------------------------------------------------------------------------
-SELECT `gen_attr_0` AS `key`, `gen_attr_1` AS `min(value)` FROM (SELECT `gen_attr_0`, `gen_attr_1` FROM (SELECT `gen_attr_0`, min(`gen_attr_5`) AS `gen_attr_1`, min(`gen_attr_5`) AS `gen_attr_4` FROM (SELECT `key` AS `gen_attr_0`, `value` AS `gen_attr_5` FROM `default`.`src`) AS gen_subquery_0 GROUP BY `gen_attr_0` HAVING (struct(`gen_attr_0`, `gen_attr_4`) IN (SELECT `gen_attr_6` AS `_c0`, `gen_attr_7` AS `_c1` FROM (SELECT `gen_attr_2` AS `gen_attr_6`, `gen_attr_3` AS `gen_attr_7` FROM (SELECT `gen_attr_2`, `gen_attr_3` FROM (SELECT `key` AS `gen_attr_2`, `value` AS `gen_attr_3` FROM `default`.`src`) AS gen_subquery_3 WHERE (`gen_attr_3` > 'val_9')) AS gen_subquery_2) AS gen_subquery_4))) AS gen_subquery_1 ORDER BY `gen_attr_0` ASC NULLS FIRST) AS b
+SELECT `gen_attr_0` AS `key`, `gen_attr_1` AS `min(value)` FROM (SELECT `gen_attr_0`, `gen_attr_1` FROM (SELECT `gen_attr_0`, min(`gen_attr_5`) AS `gen_attr_1`, min(`gen_attr_5`) AS `gen_attr_4` FROM (SELECT `key` AS `gen_attr_0`, `value` AS `gen_attr_5` FROM `default`.`src`) AS gen_subquery_0 GROUP BY `gen_attr_0` HAVING (named_struct('gen_attr_0', `gen_attr_0`, 'gen_attr_4', `gen_attr_4`) IN (SELECT `gen_attr_6` AS `_c0`, `gen_attr_7` AS `_c1` FROM (SELECT `gen_attr_2` AS `gen_attr_6`, `gen_attr_3` AS `gen_attr_7` FROM (SELECT `gen_attr_2`, `gen_attr_3` FROM (SELECT `key` AS `gen_attr_2`, `value` AS `gen_attr_3` FROM `default`.`src`) AS gen_subquery_3 WHERE (`gen_attr_3` > 'val_9')) AS gen_subquery_2) AS gen_subquery_4))) AS gen_subquery_1 ORDER BY `gen_attr_0` ASC NULLS FIRST) AS b