Fix class Time

Code:
```php
$time = new Time(0);
$time->millisecond();
```
Error:
```
Fatal error: Uncaught exception 'php\lang\JavaException' with message 'java.lang.NullPointerException' in bootstrap_test.php on line 12, position 10
Stack Trace:
#0 php\time\Time->millisecond() called at [bootstrap_test.php:12]
#1 {main}
  thrown in bootstrap_test.php on line 12

JVM Stack trace:
  php.runtime.ext.core.classes.time.WrapTime.millisecond(WrapTime.java:154)
  java.lang.reflect.Method.invoke(Method.java:483)
  php.runtime.reflection.MethodEntity.invokeDynamic(MethodEntity.java:236)
  php.runtime.invoke.ObjectInvokeHelper.invokeMethod(ObjectInvokeHelper.java:178)
  include (bootstrap_test.php:10)
  java.lang.reflect.Method.invoke(Method.java:483)
  php.runtime.reflection.ModuleEntity.include(ModuleEntity.java:77)
  php.runtime.launcher.Launcher.run(Launcher.java:203)
  php.runtime.launcher.Launcher.run(Launcher.java:179)
  php.runtime.launcher.Launcher.run(Launcher.java:175)
  php.runtime.launcher.Launcher.main(Launcher.java:236)
```