[ASTDump] Mark variadic declarations with a tag instead of child node

Summary:
This makes it easier to separate traversal of the AST from output
generation.

Reviewers: aaron.ballman

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D56751

llvm-svn: 351597
diff --git a/clang/lib/AST/TextNodeDumper.cpp b/clang/lib/AST/TextNodeDumper.cpp
index b51a900..a514f85 100644
--- a/clang/lib/AST/TextNodeDumper.cpp
+++ b/clang/lib/AST/TextNodeDumper.cpp
@@ -1096,6 +1096,8 @@
     OS << " volatile";
   if (T->isRestrict())
     OS << " restrict";
+  if (T->getExtProtoInfo().Variadic)
+    OS << " variadic";
   switch (EPI.RefQualifier) {
   case RQ_None:
     break;