Optimizing: Move GraphChecker memory allocations to arena.

Bug: 18120045
Change-Id: I3934158e6ea4868d9baa1dfcc53b603ca6c521e2
diff --git a/runtime/base/arena_allocator.cc b/runtime/base/arena_allocator.cc
index 7aa71f9..1704688 100644
--- a/runtime/base/arena_allocator.cc
+++ b/runtime/base/arena_allocator.cc
@@ -93,6 +93,7 @@
   "StackMapStm  ",
   "CodeGen      ",
   "ParallelMove ",
+  "GraphChecker ",
 };
 
 template <bool kCount>