Merge "Improving jank tests diagnostics" into pi-dev

    dprintf(fd, "\nStats since: %" PRIu64 "ns", mStatStartTime);

    dprintf(fd, "\nTotal frames rendered: %u", mTotalFrameCount);

    dprintf(fd, "\nJanky frames: %u (%.2f%%)", mJankFrameCount,

            mTotalFrameCount == 0 ? 0.0f :

                (float)mJankFrameCount / (float)mTotalFrameCount * 100.0f);

    dprintf(fd, "\n50th percentile: %ums", findPercentile(50));

    dprintf(fd, "\n90th percentile: %ums", findPercentile(90));