confused result when cast timestamp with timezone to date32

[liukun4515]

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cast from timestamp with timezone to date32

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I modify the test_cast_timestamp_to_date32 UT to get the result of

apache/datafusion#9982

The result of

        let array =
            TimestampMillisecondArray::from(vec![Some(25201000), Some(111599000), None])
                .with_timezone("-07:00".to_string());

is

PrimitiveArray<Timestamp(Millisecond, Some("-07:00"))>
[
  1970-01-01T00:00:01-07:00,
  **1970-01-01T23:59:59-07:00,**
  null,
]

the second value of timestamp is 1970-01-01T23:59:59-07:00, but the result of date32 is 1970-01-02.

It's confused with me, and also is different from other engine.

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[liukun4515]

@tustvold @waitingkuo