AsmPrinter: More explicitly scope iterator for MSVC

r240748 seems to be on the right path.  Be more explicit.

http://lab.llvm.org:8011/builders/clang-x64-ninja-win7/builds/1961/

llvm-svn: 240750

llvm/include/llvm/CodeGen/DIE.h

@@ -513,7 +513,7 @@ public:
   public:
     const_iterator() = default;
     // Placate MSVC by explicitly scoping 'iterator'.
-    const_iterator(IntrusiveBackList::iterator X) : N(X.N) {}
+    const_iterator(typename IntrusiveBackList<T>::iterator X) : N(X.N) {}
     explicit const_iterator(const T *N) : N(N) {}
 
     const_iterator &operator++() {