Flight SQL JDBC: Fix timezone/timestamp handling

### Describe the enhancement requested

I believe the JDBC driver is handling timezones/timestamps/java.sql.Timestamp entirely incorrectly.

- Timestamps are round-tripped through LocalDateTime always. I believe this is wrong for timestamps with timezones: we should not round trip through a wall clock time since the same wall clock time may correspond to multiple different instants (during a DST transition)
- From experimenting with the PostgreSQL JDBC driver, it appears that when requesting a java.sql.Timestamp, the expected behavior is:

- Naive timestamp: return a Timestamp that appears to have the right wall clock time in the given Calendar, or the system time zone if no calendar is supplied. (In other words, use Timestamp as a janky LocalDateTime.)
- Zoned timestamp: return a Timestamp whose value is the timestamp in UTC. (In other words, use Timestamp as an Instant.)

It appears our driver does not do this properly.

首先追蹤 Flight SQL JDBC driver 對 java.sql.Timestamp、LocalDateTime、時區和 Calendar 的處理方式，並將其行為與 issue 中描述的 PostgreSQL JDBC 預期進行比較。完成的標準是：無時區時間戳保留要求的牆上時鐘值，帶時區的時間戳保留 UTC 時刻，包括跨越 DST 轉換時的行為。

由索引模型根據 Issue 內容生成。