Description

APCu cache adapter works when apc.enabled is on, however, in CLI mode with the apc.enable_cli turned off, the adapter generates a lot of messages like Failed to save key.
For the system cache, this was fixed in #23390 by installing NullLogger in the adapter.
However, the problem persists for example in this configuration:

framework:
    cache:
        pools:
            cache.default:
                adapters:
                    - cache.adapter.apcu
                    - cache.adapter.redis

I suggest checking the apc.enable_cli option in each method, and do nothing in CLI mode, don't try to call acpu functions.
Something like this:

protected function doFetch(array $ids)
{
    if ('cli' === \PHP_SAPI && !filter_var(ini_get('apc.enable_cli'), FILTER_VALIDATE_BOOLEAN)) {
        return [];
    }

    ...
}

If this is a good solution, I will create a PR. If not, what decision do you think would be good?