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.

Comece rastreando como o Flight SQL JDBC driver lida com java.sql.Timestamp, LocalDateTime, fusos horários e Calendar, comparando o comportamento com as expectativas do PostgreSQL JDBC descritas na issue. Considera-se concluído quando timestamps ingênuos preservam o valor de horário de parede solicitado e timestamps com fuso preservam o instante UTC, incluindo o comportamento durante transições de DST.

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