Set valid classloader for Iceberg CTAS with delete files

[homar]

Description

Is this change a fix, improvement, new feature, refactoring, or other?

fix

Is this a change to the core query engine, a connector, client library, or the SPI interfaces? (be specific)

iceberg connector

How would you describe this change to a non-technical end user or system administrator?

a fix for a problem which could occurre in a very specific situation

Related issues, pull requests, and links

#13035

Documentation

(x) No documentation is needed.
( ) Sufficient documentation is included in this PR.
( ) Documentation PR is available with #prnumber.
( ) Documentation issue #issuenumber is filed, and can be handled later.

Release notes

(x) No release notes entries required.
( ) Release notes entries required with the following suggested text:

# Section
* Fix some things. ({issue}`issuenumber`)

[findinpath]

I've tried to test the code on this branch and ran into the following problem:

trino:default> create table iceberg.default.lineitem as select * from tpch.sf1.lineitem;
CREATE TABLE: 6001215 rows

Query 20220704_104259_00001_p7usw, FINISHED, 1 node
Splits: 22 total, 22 done (100.00%)
31.61 [6M rows, 0B] [190K rows/s, 0B/s]

trino:default> delete from iceberg.default.lineitem where extendedprice = 1000;

Query 20220704_104337_00002_p7usw, FAILED, 1 node
Splits: 11 total, 0 done (0.00%)
1.55 [0 rows, 0B] [0 rows/s, 0B/s]

Query 20220704_104337_00002_p7usw failed: UpdatablePageSource not set