Optimizing: Tag arena allocations in HGraph.

Replace GrowableArray with ArenaVector in HGraph and related
classes HEnvironment, HLoopInformation, HInvoke and HPhi,
and tag allocations with new arena allocation types.

Change-Id: I3d79897af405b9a1a5b98bfc372e70fe0b3bc40d
diff --git a/compiler/optimizing/code_generator_arm64.h b/compiler/optimizing/code_generator_arm64.h
index 12ead7e..7ebe884 100644
--- a/compiler/optimizing/code_generator_arm64.h
+++ b/compiler/optimizing/code_generator_arm64.h
@@ -326,7 +326,7 @@
 
   void Initialize() OVERRIDE {
     HGraph* graph = GetGraph();
-    int length = graph->GetBlocks().Size();
+    int length = graph->GetBlocks().size();
     block_labels_ = graph->GetArena()->AllocArray<vixl::Label>(length);
     for (int i = 0; i < length; ++i) {
       new(block_labels_ + i) vixl::Label();