Fix reset() to zero slowFrameCounts

Change-Id: I9f7f7280bcd28c361e5665de39a4bd7c594ab521
Fixes: 26386641
diff --git a/libs/hwui/JankTracker.cpp b/libs/hwui/JankTracker.cpp
index d1ff670..9d4eccc 100644
--- a/libs/hwui/JankTracker.cpp
+++ b/libs/hwui/JankTracker.cpp
@@ -285,6 +285,7 @@
 void JankTracker::reset() {
     mData->jankTypeCounts.fill(0);
     mData->frameCounts.fill(0);
+    mData->slowFrameCounts.fill(0);
     mData->totalFrameCount = 0;
     mData->jankFrameCount = 0;
     mData->statStartTime = systemTime(CLOCK_MONOTONIC);