Optimizing: Move GraphChecker memory allocations to arena.

Bug: 18120045
Change-Id: I3934158e6ea4868d9baa1dfcc53b603ca6c521e2
diff --git a/compiler/optimizing/optimizing_compiler.cc b/compiler/optimizing/optimizing_compiler.cc
index b501980..c7f0806 100644
--- a/compiler/optimizing/optimizing_compiler.cc
+++ b/compiler/optimizing/optimizing_compiler.cc
@@ -169,13 +169,13 @@
     if (kIsDebugBuild) {
       if (!graph_in_bad_state_) {
         if (graph_->IsInSsaForm()) {
-          SSAChecker checker(graph_->GetArena(), graph_);
+          SSAChecker checker(graph_);
           checker.Run();
           if (!checker.IsValid()) {
             LOG(FATAL) << "Error after " << pass_name << ": " << Dumpable<SSAChecker>(checker);
           }
         } else {
-          GraphChecker checker(graph_->GetArena(), graph_);
+          GraphChecker checker(graph_);
           checker.Run();
           if (!checker.IsValid()) {
             LOG(FATAL) << "Error after " << pass_name << ": " << Dumpable<GraphChecker>(checker);