Remove explicit double alignment from allocation helper functions.

src/heap/heap.h

Index: src/heap/heap.h
diff --git a/src/heap/heap.h b/src/heap/heap.h
index dfbcc701e6939f5a7215d19c9118f09440fe9121..1b301403b35e717e0bf2b896ae50bc4bda0930c1 100644
--- a/src/heap/heap.h
+++ b/src/heap/heap.h
@@ -1815,12 +1815,15 @@ class Heap {
 
   HeapObject* DoubleAlignForDeserialization(HeapObject* object, int size);
 
+  enum Alignment { kWordAligned, kDoubleAligned };
+
   // Allocate an uninitialized object.  The memory is non-executable if the
   // hardware and OS allow.  This is the single choke-point for allocations
   // performed by the runtime and should not be bypassed (to extend this to
   // inlined allocations, use the Heap::DisableInlineAllocation() support).
   MUST_USE_RESULT inline AllocationResult AllocateRaw(
-      int size_in_bytes, AllocationSpace space, AllocationSpace retry_space);
+      int size_in_bytes, AllocationSpace space, AllocationSpace retry_space,
+      Alignment aligment = kWordAligned);
 
   // Allocates a heap object based on the map.
   MUST_USE_RESULT AllocationResult