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/locations.h b/compiler/optimizing/locations.h
index 4b25046..cc3b35b 100644
--- a/compiler/optimizing/locations.h
+++ b/compiler/optimizing/locations.h
@@ -35,7 +35,7 @@
  * A Location is an abstraction over the potential location
  * of an instruction. It could be in register or stack.
  */
-class Location : public ValueObject {
+class Location {
  public:
   enum OutputOverlap {
     kOutputOverlap,
@@ -84,7 +84,7 @@
     DCHECK(!IsValid());
   }
 
-  Location(const Location& other) : ValueObject(), value_(other.value_) {}
+  Location(const Location& other) : value_(other.value_) {}
 
   Location& operator=(const Location& other) {
     value_ = other.value_;