Add an assert to ensure we never allocate second empty fixed array.

Review URL: http://codereview.chromium.org/3442012

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5514 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/heap.cc

@@ -3195,6 +3195,7 @@ Object* Heap::AllocateRawFixedArray(int length) {
   if (length < 0 || length > FixedArray::kMaxLength) {
     return Failure::OutOfMemoryException();
   }
+  ASSERT(length > 0);
   // Use the general function if we're forced to always allocate.
   if (always_allocate()) return AllocateFixedArray(length, TENURED);
   // Allocate the raw data for a fixed array.