[DOC] Add DR1734 and DR1496 Clang's cxx_dr_status as not implemented

[royjacobson]

Summary

Those two DRs about the (copy) triviality of types with deleted special member functions are not implemented in Clang.
Document them as such.

[aaron.ballman]

Thanks for the updated tests! Some minor commenting suggestions (that will need to be re-flowed to 80 col limit), but otherwise LGTM!

clang/test/CXX/drs/dr14xx.cpp

510

clang/test/CXX/drs/dr17xx.cpp

35

[royjacobson]

Update comments

[royjacobson]

Thanks for the suggestions and for the quick review! @aaron.ballman

clang/test/CXX/drs/dr14xx.cpp

#if __cplusplus >= 201402L
   template<typename, typename...> int b; // expected-note {{template is declared here}}
   template<typename ...Ts> int b<Ts...>; // expected-error {{not more specialized}}
 
   // Deduction fails in both directions.
   template<int, typename, typename ...> int c; // expected-note {{template is declared here}}
   template<typename ...Ts> int c<0, Ts...>; // expected-error {{not more specialized}}
 #endif
 }
+
+namespace dr1496 { // dr1496: no
+#if __cplusplus >= 201103L
+struct A {
+    A() = delete;
+};
+// FIXME: 'A' should not be trivial because the class lacks at least one
+// default constructor which is not deleted.
+static_assert(__is_trivial(A), "");
+#endif
+}
+
 #endif

clang/test/CXX/drs/dr17xx.cpp

#if __cplusplus >= 201103L
   };
 
   B b(S(), 1);
   D d(S(), 2);
   E e(S(), 3); // expected-error {{no match}}
 #endif
 }
 
+namespace dr1734 { // dr1734: no
+#if __cplusplus >= 201103L
+struct A {
+    A(const A&) = delete;
+};
+// FIXME: 'A' should not be trivially copyable because the class lacks at least
+// one non-deleted copy constructor, move constructor, copy assignment
+// operator, or move assignment operator.
+static_assert(__is_trivially_copyable(A), "");
+#endif
+}
+
 namespace dr1736 { // dr1736: 3.9
 #if __cplusplus >= 201103L
 struct S {
   template <class T> S(T t) {
     struct L : S {
       using S::S;
     };
     typename T::type value; // expected-error {{no member}}

clang/www/cxx_dr_status.html

<tr id="1495">
     <td>CD3</td>
     <td>Partial specialization of variadic class template</td>
     <td class="full" align="center">Clang 4</td>
   </tr>
   <tr id="1496">
     <td><a href="https://wg21.link/cwg1496">1496</a></td>
     <td>CD4</td>
     <td>Triviality with deleted and missing default constructors</td>
-    <td class="none" align="center">Unknown</td>
+    <td class="none" align="center">No</td>
   </tr>
   <tr id="1497">
     <td><a href="https://wg21.link/cwg1497">1497</a></td>
     <td>NAD</td>
     <td>Aggregate initialization with parenthesized string literal</td>
     <td class="none" align="center">Unknown</td>
   </tr>
   <tr id="1498">
<tr id="1733">
     <td>DRWP</td>
     <td>Return type and value for <TT>operator=</TT> with <I>ref-qualifier</I></td>
     <td class="none" align="center">Unknown</td>
   </tr>
   <tr id="1734">
     <td><a href="https://wg21.link/cwg1734">1734</a></td>
     <td>CD4</td>
     <td>Nontrivial deleted copy functions</td>
-    <td class="none" align="center">Unknown</td>
+    <td class="none" align="center">No</td>
   </tr>
   <tr class="open" id="1735">
     <td><a href="https://wg21.link/cwg1735">1735</a></td>
     <td>drafting</td>
     <td>Out-of-range literals in <I>user-defined-literal</I>s</td>
     <td align="center">Not resolved</td>
   </tr>
   <tr id="1736">