[5.6] Fix *scan methods for phpredis

[ragingdave]

This adds the adapter methods to properly utilize PhpRedis commands for scan, sscan, hscan, and zscan. fixes #24222 .... take 3.

I think there was some confusion caused by myself perhaps, I fell into an old work habit where if a PR was rejected, that meant a new branch because enough was wrong that it was beyond fixing. Clearly that is not what was expected, so I noticed the merge that caused the failed tests was drawing from the original branch. I won't be making that mistake again and will just continue on the same branch for a feature, but just to be clear the branch name changed and I added a v2 on the end. I apologize for that....still relatively new to contributing.

To be clear the most current branch is fix-scan-methods-for-phpredis-v2. I do still have the old branch locally, so if it makes it easier I can just move the changes from this branch to the original and retarget the PR.

[taylorotwell]

Reverted all this. Causes tests on master to break completely and just creates way too many merge conflicts. I'm never merging this on 5.6. You can try it submit it to master if you want or let someone else handle it.

/cc @tillkruss