Use memcpy for Atomic::LoadRelaxed.

runtime/vm/atomic_win.h

Index: runtime/vm/atomic_win.h
diff --git a/runtime/vm/atomic_win.h b/runtime/vm/atomic_win.h
index 021f3adc3f9aead55edb0f563d135be09093eafd..433d32e86d52db439b6ea964e0e1bd2e300ba171 100644
--- a/runtime/vm/atomic_win.h
+++ b/runtime/vm/atomic_win.h
@@ -61,13 +61,6 @@ inline uword AtomicOperations::CompareAndSwapWord(uword* ptr,
 }
 #endif  // !defined(USING_SIMULATOR)
 
-
-inline uword AtomicOperations::LoadRelaxed(uword* ptr) {
-  // TODO(koda): Consider using C++11 <atomic> to avoid the barrier on more
-  // compilers/platforms.
-  return FetchAndAdd(reinterpret_cast<intptr_t*>(ptr), 0);
-}
-
 }  // namespace dart
 
 #endif  // VM_ATOMIC_WIN_H_