Sort out ApcuBackendTest

Thanks for working on this @yogeshmpawar.

+++ b/core/tests/Drupal/KernelTests/Core/Cache/ApcuBackendTest.php
@@ -198,9 +126,6 @@ public function testInvalidateAll() {
   public function testRemoveBin() {
-    if ($this->requirementsFail()) {
-      return;
-    }
     parent::testRemoveBin();
   }

Where we are just calling the parent and doing nothing else we can remove the entire method.

1 files changed, 0 insertions, 145 deletions. love it!

Was so about to commit this and then realised there's one more thing.

    if (class_exists('\APCUIterator')) {
      $iterator = new \APCUIterator('/^' . $key . '/');
    }
    else {
      $iterator = new \APCIterator('user', '/^' . $key . '/');
    }

This test does

 * @requires extension apcu

So this check is moot and can be:

$iterator = new \APCUIterator('/^' . $key . '/');

No need to think about apc (without the u) and no need to check if classes exist.

Also we should open a follow-up to remove Apcu4Backend from the codebase - I'm pretty sure the apcu4 is a PHP5 only thing and therefore no longer supported by Drupal.

Committed and pushed ef6a11d84a to 8.8.x and e91c5eca76 to 8.7.x. Thanks!

Backported to 8.7.x to keep the tests aligned.

This change broke PHP5 on 8.7.x - reverting. There's no need to backport the change.