fix uninitialization issue in JankTracker

We should initialize mSwapDeadline in JankTracker, or it can be a very
large randomized value and then makes jank tracker not collect concrete
jank type of frames appropriately as expected.

Bug: 161656795
Test: run cts -m CtsIncidentHostTestCases -t
   com.android.server.cts.GraphicsStatsValidationTest#testJankyDrawFrame
Change-Id: I057a50a74502918619204f9164f6a954f8e9c5de
diff --git a/libs/hwui/JankTracker.h b/libs/hwui/JankTracker.h
index 4460266..b3fbbfe 100644
--- a/libs/hwui/JankTracker.h
+++ b/libs/hwui/JankTracker.h
@@ -75,7 +75,7 @@
 
     std::array<int64_t, NUM_BUCKETS> mThresholds;
     int64_t mFrameInterval;
-    nsecs_t mSwapDeadline;
+    nsecs_t mSwapDeadline = -1;
     // The amount of time we will erase from the total duration to account
     // for SF vsync offsets with HWC2 blocking dequeueBuffers.
     // (Vsync + mDequeueBlockTolerance) is the point at which we expect