Fix GraphicsStats#findRootPath and disable CacheManager#trimMemory tests am: 24921a0325 am: 600da2e030

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/2379069

Change-Id: I9ecde4a51a6b63cad0d6e272b0a51a2a96e58e8f
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>