SF TimeStats: update build file and some cleanups

Remove the redundant part in the Android.bp file, and at the same time
remove some unused code.

Test: dumpsys SurfaceFlinger --timestats <see go/sf-timestats for args>
Bug: b/70388650
Change-Id: I5ddd63234780f4f482c4628de173ac6167b628f5
4 files changed