MSVC: Qualify `std::initializer_list` to fix name lookup when compiling 'iostream-test.c++'.

c++/src/kj/common.h

@@ -1088,7 +1088,7 @@ public:
   inline constexpr ArrayPtr(decltype(nullptr)): ptr(nullptr), size_(0) {}
   inline constexpr ArrayPtr(T* ptr, size_t size): ptr(ptr), size_(size) {}
   inline constexpr ArrayPtr(T* begin, T* end): ptr(begin), size_(end - begin) {}
-  inline KJ_CONSTEXPR() ArrayPtr(std::initializer_list<RemoveConstOrDisable<T>> init)
+  inline KJ_CONSTEXPR() ArrayPtr(::std::initializer_list<RemoveConstOrDisable<T>> init)
       : ptr(init.begin()), size_(init.size()) {}
 
   template <size_t size>