Removed Slog methods that support message formatting.

Slog is a core class provided by frameworks.jar, and these new methods
were causing performance regressions, so they were moved to a
system_server only class (com.android.server.utils.Slogf).

Test: m

Fixes: 183523451
Bug: 182476140

Change-Id: I511dd57faee194b58cf77c0c39c92dd0e876566e