FlightRecorderOptions reset date format

[Benjamin Brandl]

Hi all,

running java 14 with VM-argument -XX:FlightRecorderOptions will reset
the date format to en.

Consider following class:
```
import java.text.DateFormat;
import java.util.Calendar;
import java.util.GregorianCalendar;

public class Main
{
    public static void main( String[] args )
    {
        GregorianCalendar date = new GregorianCalendar( 2020,
Calendar.JANUARY,
            1 );
        DateFormat formatter = DateFormat.getDateTimeInstance();

        String expected = "01.01.2020, 00:00:00";
        String formatted = formatter.format( date.getTime() );

        System.out.println(
            String.format( "expected: %s%nactual:   %s", expected,
formatted ) );
    }
}
```

When running this class java 14 and with VM arguments `-
Duser.country=DE -Duser.language=de -XX:StartFlightRecording`, `date`
will be formatted to `01.01.2020, 00:00:00`.

When running this class with java 14 and VM arguments `-
Duser.country=DE -Duser.language=de -XX:StartFlightRecording
-XX:FlightRecorderOptions=stackdepth=128`, `date` will be formatted to
`2020 Jan 1 00:00:00`.

I'd expect that in both cases, the formatted date is identical.

This scenario works as expected with latest java 11.

Best regards
Ben