ART: Fix build for counting arena allocations.

Change-Id: I1fbb8cc9c4934cc81cb80c5c2107c63fd16a0a05
diff --git a/runtime/base/arena_allocator.cc b/runtime/base/arena_allocator.cc
index e37aca1..dd29404 100644
--- a/runtime/base/arena_allocator.cc
+++ b/runtime/base/arena_allocator.cc
@@ -33,7 +33,7 @@
 const char* const ArenaAllocatorStatsImpl<kCount>::kAllocNames[] = {
   "Misc       ",
   "BasicBlock ",
-  "BBList     "
+  "BBList     ",
   "BBPreds    ",
   "DfsPreOrd  ",
   "DfsPostOrd ",