logd: report statistics memory overhead

Add in to the Total Overhead the amount of storage we are
using to hold on to the statistics.

Test: see that the Total Overhead accounts for about 100K
Bug: 31942525
Change-Id: Ibe241c0bccc5a9df52395802338c8a7fc3b64104
diff --git a/logd/LogStatistics.cpp b/logd/LogStatistics.cpp
index d68bfee..d4b48ef 100644
--- a/logd/LogStatistics.cpp
+++ b/logd/LogStatistics.cpp
@@ -547,6 +547,7 @@
         }
         spaces += spaces_total;
     }
+    totalSize += sizeOf();
     if (spaces < 0) spaces = 0;
     output += android::base::StringPrintf("%*s%zu", spaces, "", totalSize);