Provide member function definitions to avoid warnings. Patch from STL@microsoft.com

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@267843 91177308-0d34-0410-b5e6-96231b3b80d8

test/std/utilities/meta/meta.rel/is_nothrow_callable.pass.cpp

@@ -53,7 +53,7 @@ constexpr bool throws_callable() {
 // once implementations have caught up.
 void test_noexcept_function_pointers()
 {
-    struct Dummy { void foo() noexcept; static void bar() noexcept; };
+    struct Dummy { void foo() noexcept {} static void bar() noexcept {} };
 #if !defined(__cpp_noexcept_function_type)
     {
         // Check that PMF's and function pointers *work*. is_nothrow_callable will always