getTimeTry() was never being passed a null timezone, so don't check for that.…

getTimeTry() was never being passed a null timezone, so don't check for that. Rather check if the timezone is still the default, so we can use the local cached Calendar.

h2/src/main/org/h2/util/DateTimeUtils.java

@@ -387,7 +387,7 @@ public class DateTimeUtils {
             int year, int month, int day, int hour, int minute, int second,
             int millis) {
         Calendar c;
-        if (tz == null) {
+        if (tz == TimeZone.getDefault()) {
             c = getCalendar();
         } else {
             c = Calendar.getInstance(tz);