Use route name and params instead of _system_path in FormSubmitter

Here is one.

meh

Reasons for this interdiff: ElementsTableSelectTest executes form processing code in a simpletest, so the route name is not set on the route match object.

trying...

1. +++ b/core/lib/Drupal/Core/Form/FormSubmitter.php
   @@ -137,19 +149,14 @@ public function redirectForm(FormStateInterface $form_state) {
   -    if ($url) {
   -      // According to RFC 7231, 303 See Other status code must be used to redirect
   -      // user agent (and not default 302 Found).
   -      // @see http://tools.ietf.org/html/rfc7231#section-6.4.4
   -      return new RedirectResponse($url, Response::HTTP_SEE_OTHER);
   ...
   +        return new RedirectResponse($url, Response::HTTP_SEE_OTHER);
   

   This still needs to be outside of that, left as-is. See the if() case above

2. +++ b/core/lib/Drupal/Core/Form/FormSubmitter.php
   @@ -137,19 +149,14 @@ public function redirectForm(FormStateInterface $form_state) {
   +        $url = $this->urlGenerator->generateFromRoute($this->routeMatch->getRouteName(), $this->routeMatch->getRawParameters()
   +          ->all(), array(
   +          'query' => $request->query->all(),
   +          'absolute' => TRUE,
   +        ));
   

   This should be in the elseif

@tim.plunkett thank you.
here the patch

So PHP Fatal error introduced in:

+      $url = $this->urlGenerator->generateFromRoute($this->routeMatch->getRouteName(), $this->routeMatch->getRawParameters()
+        ->all(), array(

Ok, so what has all() been replaced with in getRawParameters()?

@rpayanm you should really install dreditor, the browser extension. It'll give you a button in the files section where you go to upload your patch with a "patchname suggestion" button. It'll help give you a standard patchname for the issue. Not to pick on you, the other two prior posters didn't use it either, it's just getting to be a pet peeve. If we all just used the patchname suggestion button, it would make creating the interdiffs so much easier.
And that is one thing you really should do, @rpayanm, when submitting patchs, is submit a corresponding interdiff at the same time. It helps everyone who is following the issue.
Attaching interdiffs from 6 to 9, and 9 to 11.

Straight reroll of #11.
Let us see where Testbot is the most angry.

drink Druplicon!

Sorry but this is basically a duplicate of #2372507: Remove _system_path from $request->attributes :(