Clean up more usages of _LIBCPP_HAS_NO_RVALUE_REFERENCES

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@296854 91177308-0d34-0410-b5e6-96231b3b80d8

test/std/thread/thread.threads/thread.thread.class/thread.thread.constr/move.pass.cpp

@@ -7,7 +7,7 @@
 //
 //===----------------------------------------------------------------------===//
 //
-// UNSUPPORTED: libcpp-has-no-threads
+// UNSUPPORTED: libcpp-has-no-threads, c++98, c++03
 
 // <thread>
 
@@ -53,7 +53,6 @@ bool G::op_run = false;
 
 int main()
 {
-#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
     {
         G g;
         assert(G::n_alive == 1);
@@ -68,5 +67,4 @@ int main()
         assert(G::op_run);
     }
     assert(G::n_alive == 0);
-#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
 }