Fix bad use of OffsetFrom that fails on ARM (sizeof(Object) wasn't 1).

src/heap-inl.h

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 115 matching lines @@
 Object* Heap::AllocateRawMap() {
 #ifdef DEBUG
   Counters::objs_since_last_full.Increment();
   Counters::objs_since_last_young.Increment();
 #endif
   Object* result = map_space_->AllocateRaw(Map::kSize);
   if (result->IsFailure()) old_gen_exhausted_ = true;
 #ifdef DEBUG
   if (!result->IsFailure()) {
     // Maps have their own alignment.
-    CHECK((OffsetFrom(result) & kMapAlignmentMask) == kHeapObjectTag);
+    CHECK_EQ(static_cast<intptr_t>(kHeapObjectTag),
+             reinterpret_cast<intptr_t>(result) & kMapAlignmentMask);
   }
 #endif
   return result;
 }
 
 
 Object* Heap::AllocateRawCell() {
 #ifdef DEBUG
   Counters::objs_since_last_full.Increment();
   Counters::objs_since_last_young.Increment();
@@ skipping 267 matching lines @@
 
 
 void ExternalStringTable::ShrinkNewStrings(int position) {
   new_space_strings_.Rewind(position);
   Verify();
 }
 
 } }  // namespace v8::internal
 
 #endif  // V8_HEAP_INL_H_