Describe the bug

UT case timestamp_add_interval_months failed to run on master (commit 3d37016)

To Reproduce

git checkout 3d37016de3647d90e6f78fd0e106142923799969
cargo test

I got this error:

thread 'sql::timestamp::timestamp_add_interval_months' panicked at 'called `Option::unwrap()` on a `None` value', datafusion/core/tests/sql/timestamp.rs:1414:58

Expected behavior

Pass this test

Additional context
Add any other context about the problem here.