[msan] Do not unpoison heap if running on simulator.

src/spaces.cc

 // Copyright 2011 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 693 matching lines @@
   }
 
   MemoryChunk* result = MemoryChunk::Initialize(heap,
                                                 base,
                                                 chunk_size,
                                                 area_start,
                                                 area_end,
                                                 executable,
                                                 owner);
   result->set_reserved_memory(&reservation);
-  MSAN_MEMORY_IS_INITIALIZED(base, chunk_size);
+  MSAN_MEMORY_IS_INITIALIZED_IN_JIT(base, chunk_size);
   return result;
 }
 
 
 void Page::ResetFreeListStatistics() {
   non_available_small_blocks_ = 0;
   available_in_small_free_list_ = 0;
   available_in_medium_free_list_ = 0;
   available_in_large_free_list_ = 0;
   available_in_huge_free_list_ = 0;
@@ skipping 2474 matching lines @@
     object->ShortPrint();
     PrintF("\n");
   }
   printf(" --------------------------------------\n");
   printf(" Marked: %x, LiveCount: %x\n", mark_size, LiveBytes());
 }
 
 #endif  // DEBUG
 
 } }  // namespace v8::internal