Fixed ImageWriter timings not being written out.

During host runs of dex2oat the timings for ImageWriter would not be
written out.

Change-Id: I74ce8bae724d1e732a6a1efb1c82804473081693
diff --git a/dex2oat/dex2oat.cc b/dex2oat/dex2oat.cc
index 38051ea..4be6d87 100644
--- a/dex2oat/dex2oat.cc
+++ b/dex2oat/dex2oat.cc
@@ -1461,6 +1461,7 @@
   }
 
   if (is_host) {
+    timings.EndSplit();
     if (dump_timing || (dump_slow_timing && timings.GetTotalNs() > MsToNs(1000))) {
       LOG(INFO) << Dumpable<TimingLogger>(timings);
     }