new considered harmful

I'm committing my work on HphpArray in bite-sized pieces for easier review. This piece replaces calls to NEW with a factory method. There are many problems with operator new, starting with the fact that the allocator cannot communicate properly with the constructor.

The newly introduced factory method should return ArrayData but that causes many issues right now, so I left that step to a future diff.

hphp/runtime/base/array/array_init.cpp

@@ -30,18 +30,18 @@ ArrayInit::ArrayInit(ssize_t n) {
     // Force compilation of ArrayShell
     m_data = NEW(ArrayShell)(n);
   } else {
-    m_data = NEW(HphpArray)(n);
+    m_data = ArrayData::Make(n);
   }
 }
 
 HOT_FUNC
 ArrayData *ArrayInit::CreateVector(ssize_t n) {
-  return NEW(HphpArray)(n);
+  return ArrayData::Make(n);
 }
 
 HOT_FUNC
 ArrayData *ArrayInit::CreateMap(ssize_t n) {
-  return NEW(HphpArray)(n);
+  return ArrayData::Make(n);
 }
 
 ArrayData *ArrayInit::CreateParams(int count, ...) {