Description:
------------
Somehow, creating two DateTime objects from the same date input string, and then setting all of the time values to be 0 manages to create one of them with the wrong microseconds.

I have a testsuite that includes a test for creating a datetime object from user input and comparing them against a DateTime object created from set parameters. This test has worked for months, but just now failed twice in a row, and the DateTimes were different.

-2002-10-02T00:00:00.000001+0000
+2002-10-02T00:00:00.000000+0000

The code below is _not_ a reproduce case, but shows what PHPUnit was doing to compare the DateTimes. 

Not expecting this to be fixed as high chance it was something specific to my system, more just creating the report for posterity

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

declare(strict_types = 1);


$max = 1000000;
$formatString = \DateTimeInterface::RFC3339_EXTENDED;
$absDelta = 0.0;

for ($i = 0; $i < $max; $i += 1) {
    $actual = \DateTimeImmutable::createFromFormat('Y-m-d', '2002-10-02');
    if ($actual instanceof \DateTimeImmutable) {
        $actual = $actual->setTime(0, 0, 0, 0);
    }
    usleep(rand(0, 1000));

    $expected = \DateTime::createFromFormat('Y-m-d', '2002-10-02')->setTime(0, 0, 0, 0);
    $delta    = new \DateInterval(\sprintf('PT%dS', $absDelta));
    $actualClone = (clone $actual)
        ->setTimezone(new \DateTimeZone('UTC'));

    usleep(rand(0, 1000));

    $expectedLower = (clone $expected)
        ->setTimezone(new \DateTimeZone('UTC'))
        ->sub($delta);

    usleep(rand(0, 1000));

    $expectedUpper = (clone $expected)
        ->setTimezone(new \DateTimeZone('UTC'))
        ->add($delta);

    if ($actualClone < $expectedLower || $actualClone > $expectedUpper) {
        $string1 = $expected->format($formatString);
        $string2 = $actual->format($formatString);

        echo "Odd\n";
        echo $string1 . "\n";
        echo $string2 . "\n";
        exit(0);
    }

    if ($i % ($max / 100) === 0) {
        echo ".";
    }
    if ($i % ($max / 10) === 0) {
        echo "\n";
    }
}

echo "fin";