reduce flunctuation in boot animation start / stopping time

- Add separate 100ms interval polling for SurfaceFlinger. Otherwise,
  it can be blocked with 1 sec polling and cause 1 sec of additional
  delay frequently.

bug: 38450031
bug: 35253872
Test: many reboots and check time to finish boot animation, python packages/services/Car/tools/bootanalyze/bootanalyze.py -r -c packages/services/Car/tools/bootanalyze/config.yaml -n 100 -f -e 15 -w 30 -v

Change-Id: I353ca04183cbe59b82da99dc3fecfce63314cd2f