[test](be) Add table reader edge case unit tests

[Gabriel39]

What problem does this PR solve?

Issue Number: close #xxx

Related PR: #63893

Problem Summary: Add focused BE unit coverage for new table reader and new parquet reader edge cases, including aggregate pushdown over split ranges, Iceberg equality/position deletes, row lineage after delete filtering, Parquet dictionary/statistics pruning, and IOContext release. Also clean up temporary delete predicate expression columns in the new Parquet reader so equality delete predicates with cast children do not alter the returned file block schema.

Release note

None

Check List (For Author)

• Test: Unit Test
  • Added BE UT cases in table_reader_test and parquet_reader_test.
  • Ran git diff --check.
  • Tried ./run-be-ut.sh with focused filters, but local JAVA_HOME points to JDK 11 and JDK_17 is not set; the runner requires JDK 17.
• Behavior changed: No
• Does this need documentation: No

What problem does this PR solve?

Issue Number: close #xxx

Related PR: #xxx

Problem Summary:

Release note

None

Check List (For Author)

• Test

  • Regression test
  • Unit Test
  • Manual test (add detailed scripts or steps below)
  • No need to test or manual test. Explain why:
    • This is a refactor/code format and no logic has been changed.
    • Previous test can cover this change.
    • No code files have been changed.
    • Other reason

• Behavior changed:

  • No.
  • Yes.

• Does this need documentation?

  • No.
  • Yes.

Check List (For Reviewer who merge this PR)

• Confirm the release note
• Confirm test cases
• Confirm document
• Add branch pick label

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