NFC: Move dumping of QualType node to TextNodeDumper

[aaron.ballman]

LGTM!

include/clang/AST/TextNodeDumper.h

public:
 
   void Visit(const TemplateArgument &TA, SourceRange R,
              const Decl *From = nullptr, StringRef Label = {});
 
   void Visit(const Stmt *Node);
 
   void Visit(const Type *T);
 
+  void Visit(QualType T);
+
   void dumpPointer(const void *Ptr);
   void dumpLocation(SourceLocation Loc);
   void dumpSourceRange(SourceRange R);
   void dumpBareType(QualType T, bool Desugar = true);
   void dumpType(QualType T);
   void dumpBareDeclRef(const Decl *D);
   void dumpName(const NamedDecl *ND);
   void dumpAccessSpecifier(AccessSpecifier AS);

lib/AST/ASTDumper.cpp

 //===----------------------------------------------------------------------===//
 
 void ASTDumper::dumpTypeAsChild(QualType T) {
   SplitQualType SQT = T.split();
   if (!SQT.Quals.hasQualifiers())
     return dumpTypeAsChild(SQT.Ty);
 
   dumpChild([=] {
-    OS << "QualType";
-    NodeDumper.dumpPointer(T.getAsOpaquePtr());
-    OS << " ";
-    NodeDumper.dumpBareType(T, false);
-    OS << " " << T.split().Quals.getAsString();
+    NodeDumper.Visit(T);
     dumpTypeAsChild(T.split().Ty);
   });
 }
 
 void ASTDumper::dumpTypeAsChild(const Type *T) {
   dumpChild([=] {
     NodeDumper.Visit(T);
     if (!T) {

lib/AST/TextNodeDumper.cpp

void TextNodeDumper::Visit(const Type *T) {
   if (T->isVariablyModifiedType())
     OS << " variably_modified";
   if (T->containsUnexpandedParameterPack())
     OS << " contains_unexpanded_pack";
   if (T->isFromAST())
     OS << " imported";
 }
 
+void TextNodeDumper::Visit(QualType T) {
+  OS << "QualType";
+  dumpPointer(T.getAsOpaquePtr());
+  OS << " ";
+  dumpBareType(T, false);
+  OS << " " << T.split().Quals.getAsString();
+}
+
 void TextNodeDumper::dumpPointer(const void *Ptr) {
   ColorScope Color(OS, ShowColors, AddressColor);
   OS << ' ' << Ptr;
 }
 
 void TextNodeDumper::dumpLocation(SourceLocation Loc) {
   if (!SM)
     return;