UiHelperTrait::drupalLogin() breaks with language suffix

Problem/Motivation

In UiHelperTrait::drupalLogin() we call user_pass_reset_url() to build a url for 'user.reset' route, and then append '/login?destination=user/' . $account->id().
This does not work if the url ends with a language suffix like '_en'.
We would end up with a url like '***/user/reset/552/***/_*****_en/login?destination=user/552'.

This is relevant for contrib modules that use core traits for testing.

Steps to reproduce

Create and enable a language negotiation plugin which appends a suffix like '_en' (or perhaps '/en') to the url.
Write a functional test with that module and plugin enabled.
Call ->drupalLogin() in that test.

Proposed resolution

Instead of calling user_pass_reset_url(), we build a url for 'user.reset.login', which already has the '/login' suffix.
Unfortunately there is no built-in function for that.

Given that user_pass_reset_url() is a legacy procedural function, and we will have to redesign that part of Drupal in a modern way, for now we should simply hard-code everything.

We might even refrain from adding a new method in UiHelperTrait, as this could nameclash with existing methods in contrib tests, and we might want to remove it again in the future. Instead, we just inline everything. Ugly but least disruptive.

We can backport this to as many branches as possible.

Testing: I just realized that I would need to write an entire language negotiation plugin just to test this.
This would be a lot of effort for little benefit.
Maybe people can just keep this as a patch for now.

Remaining tasks

User interface changes

Introduced terminology

API changes

Data model changes

Release notes snippet