Revert "fix a weird use of Vector::appendVector()"

This reverts commit 198fd888add624cf9e53ce31b776568a5d069916

This change seems to have exposed some other bugs.
Bug: 5026631
diff --git a/services/input/InputDispatcher.cpp b/services/input/InputDispatcher.cpp
index da9b55c..10b9083 100644
--- a/services/input/InputDispatcher.cpp
+++ b/services/input/InputDispatcher.cpp
@@ -3154,9 +3154,11 @@
             mLastHoverWindow = NULL;
         }
 
+        mWindows.clear();
+
         // Loop over new windows and rebuild the necessary window pointers for
         // tracking focus and touch.
-        mWindows = inputWindows;
+        mWindows.appendVector(inputWindows);
 
         size_t numWindows = mWindows.size();
         for (size_t i = 0; i < numWindows; i++) {
@@ -4558,7 +4560,8 @@
     split = other.split;
     deviceId = other.deviceId;
     source = other.source;
-    windows = other.windows;
+    windows.clear();
+    windows.appendVector(other.windows);
 }
 
 void InputDispatcher::TouchState::addOrUpdateWindow(const InputWindow* window,