Fix freeze rate calculations am: 2a3af65ad3 am: fe3203ca9f

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/av/+/23352136

Change-Id: I24ba2947a3ba29ea891ae91961e02526be0f3159
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>