TO_UNIX_TIMESTAMP (or UNIX_TIMESTAMP) treats argument timestamp as UTC

In previous versions (at least in 1.2) we had 

> SELECT TO_UNIX_TIMESTAMP("2018-12-25 02:00:53.297");
1545692453

Now it is

> SELECT TO_UNIX_TIMESTAMP("2018-12-25 02:00:53.297");
1545703253 

We're in +3 timezone (Europe/Moscow)

This changes was made in HIVE-12192. I don't know if it was intentional, but according to wiki unix_timestamp should use default timezone