Fix use of uninitialized memory

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@304105 91177308-0d34-0410-b5e6-96231b3b80d8

test/std/experimental/language.support/support.coroutines/end.to.end/expected.sh.cpp

@@ -41,7 +41,7 @@ struct expected {
 
   struct promise_type {
     Data* data;
-    DataPtr get_return_object() { data = new Data; return {data}; }
+    DataPtr get_return_object() { data = new Data{}; return {data}; }
     suspend_never initial_suspend() { return {}; }
     suspend_never final_suspend() { return {}; }
     void return_value(T v) { data->val = std::move(v); data->error = {};}