Description:
------------
DateTime diff method returns incorrect result when using milliseconds

This might be related to this fix introduced in 7.2.12:
https://bugs.php.net/bug.php?id=77007



Test script:
---------------
<?php

$diff = (new DateTime('2018-12-04T07:42:59.123Z'))->diff(new DateTime('2018-12-04T07:42:59.122Z');

print_r($diff);

?>

Expected result:
----------------
DateInterval Object
(
    [y] => 0
    [m] => 0
    [d] => 0
    [h] => 0
    [i] => 0
    [s] => 0
    [f] => -0.123
    [weekday] => 0
    [weekday_behavior] => 0
    [first_last_day_of] => 0
    [invert] => 0
    [days] => 0
    [special_type] => 0
    [special_amount] => 0
    [have_weekday_relative] => 0
    [have_special_relative] => 0
)

Actual result:
--------------
DateInterval Object
(
    [y] => -1
    [m] => 11
    [d] => 29
    [h] => 23
    [i] => 59
    [s] => 59
    [f] => 0.999
    [weekday] => 0
    [weekday_behavior] => 0
    [first_last_day_of] => 0
    [invert] => 0
    [days] => 0
    [special_type] => 0
    [special_amount] => 0
    [have_weekday_relative] => 0
    [have_special_relative] => 0
)