Convert AJAX part of \Drupal\user\Tests\UserPasswordResetTest to WebDriverTestBase

Patch with:
- conversion of the AJAX part to Webdriver test
- other tests to Browser test (with some speed improvement, by using the testing profile)

This looks great, just some minor clean up as far as I can see:

1. +++ b/core/modules/user/src/Tests/Functional/UserPasswordResetTest.php
   @@ -14,16 +15,9 @@
   -  protected $profile = 'standard';
   

   So nice that the browser test doesn't need this anymore!

2. +++ b/core/modules/user/src/Tests/Functional/UserPasswordResetTest.php
   @@ -239,6 +225,8 @@ public function testUserPasswordResetLoggedIn() {
   +    $this->drupalLogout();
   +    $this->drupalGet('<front>');
   

   Still weird that this is needed, but I saw it fail otherwise....so lets keep it

3. +++ b/core/modules/user/src/Tests/FunctionalJavascript/UserPasswordResetTest.php
   @@ -0,0 +1,137 @@
   +  /**
   +   * Modules to enable.
   +   *
   +   * @var array
   +   */
   

   This can just be {@inheritdoc} in the new test.

4. +++ b/core/modules/user/src/Tests/FunctionalJavascript/UserPasswordResetTest.php
   @@ -0,0 +1,137 @@
   +    // Enable page caching.
   +    $config = $this->config('system.performance');
   +    $config->set('cache.page.max_age', 3600);
   +    $config->save();
   +
   +    $this->drupalPlaceBlock('system_menu_block:account');
   

   Do we need the block in the javascript test? Don't think so, right? And the page caching?

Addressed my own feedback

#9.2 works on my machine when I take it out, lets see what the Bot thinks

The Bot, it agrees! As do I, this looks very solid and #11 resolves #9.

Committed and pushed e4146aa44f to 8.7.x and 7a3a01f34f to 8.6.x. Thanks!

Whoops, this actually forgot to move the new tests to the right spot and failed to set the right namespace!

Unfortunately the patch does not apply.

Rerolled for 8.7.x

The patch applies again.

Committed and pushed 57dfd4ba8c to 8.7.x and a42db5a7ee to 8.6.x. Thanks!