Add fix for incorrect timestamp issue

[samikshya-db]

Description

Fixes #1116

Testing

Additional Notes to the Reviewer

[AndreiRudkouski]

The current implementation of public void setTimestamp(int parameterIndex, Timestamp x, Calendar cal) throws SQLException method is dangerous because it temporarily changes the global JVM default time zone, which can break other threads and cause race conditions. However, this code is also logically incorrect: changing the default time zone does not affect the numeric value of a Timestamp, because Timestamp always stores an absolute UTC-based instant (long milliseconds). As a result, the method introduces global side effects without actually achieving its intended purpose.

If time zone adjustment is needed, you should compute the offset manually instead of modifying the global default:

long millis = x.getTime();

long adjustedMillis =
        millis
        - cal.getTimeZone().getOffset(millis)
        + TimeZone.getDefault().getOffset(millis);

Timestamp safeTs = new Timestamp(adjustedMillis);
safeTs.setNanos(x.getNanos());