Missing cache invalidation of deprecatedcapabilities cache

We run the unit tests for accesslib and all the test connected to get_deprecated_capability failed. Doing some failure research we figured out following problem: In a local plugin we observe the event \core\event\course_created and by doing so cause a capability check.
Taking as an example the test methode test_get_deprecated_capability_info(): This leads to that after $this->setup_fake_plugin('access') the flag 'deprecated_capabilities_initialised' in the cache ('core', 'deprecatedcapabilities') being already set to true before the intended setup of the test, which should happen in the call of get_deprecated_capability_info('fake/access:fakecapability').

So these unit tests fail because the new deprecated capabilities of the fake_plugin are not in the deprecatedcapabilities cache.

Maybe function update_capabilities() should note this change. It flushes the cache ('core', 'capabilities') four times:

cache::make('core', 'capabilities')->delete('core_capabilities');

but never

cache::make('core', 'deprecatedcapabilities')->delete('deprecated_capabilities_initialised');