Revert "Don't build invalid AST nodes during recovery"

This reverts commit r224451. It caused us to reject some valid existing
code.

This code appears to run in non-error cases as well as error cases. If
the scope of a DependentScopeDeclRefExpr is still incomplete it probably
means we still have more instantiation to do.

llvm-svn: 224526
diff --git a/clang/test/SemaTemplate/instantiate-dependent-nested-name.cpp b/clang/test/SemaTemplate/instantiate-dependent-nested-name.cpp
index cb2c946..06a1ed4 100644
--- a/clang/test/SemaTemplate/instantiate-dependent-nested-name.cpp
+++ b/clang/test/SemaTemplate/instantiate-dependent-nested-name.cpp
@@ -1,19 +1,8 @@
 // RUN: %clang_cc1 -fsyntax-only -verify %s
-
+// expected-no-diagnostics
 // PR4382
 template<typename T> struct X { static const T A = 1; };
 template<typename T, bool = X<T>::A> struct Y { typedef T A; };
 template<typename T> struct Z { typedef typename Y<T>::A A; };
 extern int x;
 extern Z<int>::A x;
-
-namespace pr21964 {
-struct H;
-template <class> struct T {
-  struct A; // expected-note {{member is declared here}}
-  static void B() {
-    A::template N<H>; // expected-error {{implicit instantiation of undefined member 'pr21964::T<pr21964::H>::A'}}
-  }
-};
-template struct T<H>; // expected-note {{requested here}}
-}