optional: Implement LWG 2900 and P0602

Differential Revision: https://reviews.llvm.org/D32385

llvm-svn: 307505

libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/move.pass.cpp

@@ -55,10 +55,10 @@ constexpr bool constexpr_test(InitArgs&&... args)
 void test_throwing_ctor() {
 #ifndef TEST_HAS_NO_EXCEPTIONS
     struct Z {
-      Z() : count(0) {}
-      Z(Z&& o) : count(o.count + 1)
-      { if (count == 2) throw 6; }
-      int count;
+        Z() : count(0) {}
+        Z(Z&& o) : count(o.count + 1)
+        { if (count == 2) throw 6; }
+        int count;
     };
     Z z;
     optional<Z> rhs(std::move(z));