Backed out changeset 80e9cd4126b4 (bug 1397052) for adding a hazard to the build a=backout

MozReview-Commit-ID: I5ZLNHEfj1j

--HG--
extra : rebase_source : 2fca456cfec65b668247cd6236ff1d146857f7c7

xpcom/base/nsISupportsImpl.h

@@ -357,7 +357,7 @@ public:
       // acquire semantics to synchronize with the memory released by
       // the last release on other threads, that is, to ensure that
       // writes prior to that release are now visible on this thread.
-      std::atomic_thread_fence(std::memory_order_acquire);
+      result = mValue.load(std::memory_order_acquire);
     }
     return result;
   }