Implement Display Layer Stats

Try to collect data for analyzing how many display controller layers we
need and what we use them for. Also part of a bug fixing for potential
memory leak of existing layer tracing work of winscope.

Test: adb shell dumpsys SurfaceFlinger --enable-layer-stats
Test: adb shell dumpsys SurfaceFlinger --disable-layer-stats
Test: adb shell dumpsys SurfaceFlinger --clear-layer-stats
Test: adb shell dumpsys SurfaceFlinger --dump-layer-stats
Bug: b/73668062
Change-Id: Ie08aa85d34db2c2c767b8e27eb5aad6f7c3fb975
Merged-In: Ie08aa85d34db2c2c767b8e27eb5aad6f7c3fb975