Fix systrace logging, total paused time, and bytes saved message.

Moved the GC top level systrace logging to be inside of Collector::Run.
This prevents cases where we forgot to call it such as background
compaction. Fixed a unit error regarding total pause time. Fixed
negative bytes saved to use the word "expanded".

Bug: 15702709

Change-Id: Ic2991ecad2daa000d0aee9d559b8bc77d8c160aa
diff --git a/runtime/base/histogram.h b/runtime/base/histogram.h
index a7d51e2..1e12be8 100644
--- a/runtime/base/histogram.h
+++ b/runtime/base/histogram.h
@@ -71,6 +71,10 @@
     return sum_;
   }
 
+  Value AdjustedSum() const {
+    return sum_ * kAdjust;
+  }
+
   Value Min() const {
     return min_value_added_;
   }