Fix BDateFormatTest: Consider timezone in test cases.

[akshay]

• Issue: A time_t value of say '12345678' results into different timestamps in different timezones. So the expected output will not match the result of BDateFormat::Format() if the calendar's timezone is different from the timezone of the expected output, and the tests 'TestFormat' and 'TestCustomFormat' will fail.

• Fix: Add timezone information in the test cases and pass the timezone while calling BDateFormat::Format() in order to set the calendar's timezone same as that of the expected output.

[pulkomandy]

Applied in hrev51376. Thanks!