Mark ostream_iterator's constructors as noexcept.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@284021 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/iterator b/include/iterator
index 188a480..b0f5527 100644
--- a/include/iterator
+++ b/include/iterator
@@ -889,9 +889,9 @@
     ostream_type* __out_stream_;
     const char_type* __delim_;
 public:
-    _LIBCPP_INLINE_VISIBILITY ostream_iterator(ostream_type& __s)
+    _LIBCPP_INLINE_VISIBILITY ostream_iterator(ostream_type& __s) _NOEXCEPT
         : __out_stream_(_VSTD::addressof(__s)), __delim_(0) {}
-    _LIBCPP_INLINE_VISIBILITY ostream_iterator(ostream_type& __s, const _CharT* __delimiter)
+    _LIBCPP_INLINE_VISIBILITY ostream_iterator(ostream_type& __s, const _CharT* __delimiter) _NOEXCEPT
         : __out_stream_(_VSTD::addressof(__s)), __delim_(__delimiter) {}
     _LIBCPP_INLINE_VISIBILITY ostream_iterator& operator=(const _Tp& __value_)
         {