Nuke support for running MSan without a simulator.

src/heap/spaces.cc

Index: src/heap/spaces.cc
diff --git a/src/heap/spaces.cc b/src/heap/spaces.cc
index ff55c89e5d2f34036d79a8d57e704bf9c2dd9302..a294acf40b22db82849aabb7b3716169383dd867 100644
--- a/src/heap/spaces.cc
+++ b/src/heap/spaces.cc
@@ -661,7 +661,6 @@ MemoryChunk* MemoryAllocator::AllocateChunk(intptr_t reserve_area_size,
   MemoryChunk* result = MemoryChunk::Initialize(
       heap, base, chunk_size, area_start, area_end, executable, owner);
   result->set_reserved_memory(&reservation);
-  MSAN_MEMORY_IS_INITIALIZED_IN_JIT(base, chunk_size);
   return result;
 }