init: log services requested restart

We have a case where a service is requested to be started and does
not appear to be running, but we see no indication that it is
actually starting. This log should be enough information to see
if init is in a bad state.

Bug: 232297944
Test: doesn't add too much spam
    ~/android/aosp/system/core/init :) adb logcat -d | grep "requested start" | wc -l
    42
Change-Id: Ic07f250c98b200b9e5b4432200c3668c6ca0ff35