DrupalDateTime::createFromFormat() fails when resetting.

Problem/Motivation

Creating a DrupalDateTime using the method createFromFormat I noticed that I get an exception "The created date does not match the input value" whenever i use a reset character (!|) as defined in php DateTime and referenced in the method's documentation.
From what i can see it makes the "reset" options completely unusable, without any acceptable workaround.

To reproduce this is very simple:

$format = '!dmy';
$date_str = '011195';
$date = \DateTime::createFromFormat($format, $date_str); // works
$date = \Drupal\Core\Datetime\DrupalDateTime::createFromFormat($format, $date_str);  // fails
$date = DateTimePlus::createFromFormat($format, $date_str, 'UTC'); // also fails

I did some more tests here:

$date_str = '01.11.95 09:12:00';

// Failing
$format = '!d.m.y H:i';
$date = DateTimePlus::createFromFormat($format, $date_str); 
// Failing
$format = '!d.m.y H:i:s';
$date = DateTimePlus::createFromFormat($format, $date_str); 

// Working
$format = 'd.m.y H:i:s';
$date = DateTimePlus::createFromFormat($format, $date_str); 

Proposed resolution

TBD

Remaining tasks

TBD

User interface changes

None

API changes

None

Data model changes

None