Optimize split_domain_port() by leveraging the regex

[Chris Jerdonek]

I noticed that almost all of the pure Python can be removed from Django's split_domain_port() function:
​https://github.com/django/django/blob/2f13c476abe4ba787b6cb71131818341911f43cc/django/http/request.py#L643-L650
by modifying the host_validation_re regex slightly and then accessing it via its groups:
​https://github.com/django/django/blob/2f13c476abe4ba787b6cb71131818341911f43cc/django/http/request.py#L26
Currently, the function uses the regex to determine if there's a match, and then uses pure Python to reparse out the components (work which the regex has already done for the most part).

I can do this once accepted.

[Mariusz Felisiak]

Thanks for the suggestion, this optimization has already been proposed as a part of #31354, see ​PR. I think we can keep it there and merge it before the main fix.

[Chris Jerdonek]

Thanks for the pointer. That PR doesn't contain all the optimizations I had in mind, though. There is more pure Python that can be removed.

[Chris Jerdonek]

I was also going to add more tests as part of my change because currently there is only one test case (testing dot removal): ​https://github.com/django/django/blob/2f13c476abe4ba787b6cb71131818341911f43cc/tests/requests/tests.py#L813-L816