New 'Drupal\Component\DependencyInjection\ReverseContainer' service to replace DrupalKernel::getServiceIdMapping()

Of the 130 remaining test failures, this issue seems to be responsible for 129.

Testing shows that these tests do not fail in Drupal 10.0, but only in 10.1 when the bc layer for this change was removed.

The only tests that fail are Unit tests, which is consistent with my suspicion above.

Experimenting with fixes - let's see what happens if we try this.

Because ReverseContainer didn't exist before D9.5, I expect we will have to add some conditional code to the tests to ensure they work with both D9 and D10. This patch doesn't have that conditional code, so what I'm primarily hoping for is that the ReverseContainer errors go away in the D10.1 tests.

Well that didn't work. Apparently because D10.1 uses the almost-fully-qualified class name Drupal\Core\DependencyInjection\ReverseContainer(without the initial "\") as a service ID instead of a regular service ID.

Let's try that again.

Ah, that didn't work either.

After all this I looked more closely and I discovered that although the change record and the core documentation say this class is:
Drupal\Core\DependencyInjection\ReverseContainer
it is actually:
Drupal\Component\DependencyInjection\ReverseContainer

So that was a waste of time. Trying a new patch with the correct class name ... I'll have to go in and edit the change record to make sure no one else wastes time on this.

That fixed all the "ReverseContainer" errors in D9 and D10. There is 1 test fail left in D10, but that's a different issue entirely.

Committed with coding standards fix.

Note, this only affected the TESTS and not the actual Rules code that would execute on a website.