Extension.Get API action filtering is broken

As far as I can tell, the *Extension.Get* no longer acts correctly - regardless of what filter parameters I provide, I get 25 results back. When I attempt to use *GetSingle*, I get a "expected 1 result, got 25" error.

This is replicated on dmaster when attempting to filter by Name or Key:

I believe this was introduced in PR-9141, as the call to `_civicrm_api3_basic_array_get` has the "filterable fields" parameter changed to an empty array.