[heap] Remove dead code DoubleAlignForDeserialization

Bug: 
Change-Id: I8db893ac46ad82e52ff2918336107d55600789a5
Reviewed-on: https://chromium-review.googlesource.com/628542Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47550}

src/heap/heap.cc

@@ -2246,12 +2246,6 @@ HeapObject* Heap::AlignWithFiller(HeapObject* object, int object_size,
   return object;
 }
 
-
-HeapObject* Heap::DoubleAlignForDeserialization(HeapObject* object, int size) {
-  return AlignWithFiller(object, size - kPointerSize, size, kDoubleAligned);
-}
-
-
 void Heap::RegisterNewArrayBuffer(JSArrayBuffer* buffer) {
   ArrayBufferTracker::RegisterNew(this, buffer);
 }

src/heap/heap.h

@@ -1734,8 +1734,6 @@ class Heap {
 
   void CreateFixedStubs();
 
-  HeapObject* DoubleAlignForDeserialization(HeapObject* object, int size);
-
   // Commits from space if it is uncommitted.
   void EnsureFromSpaceIsCommitted();