[OpenCL] Fix pipe type dump.

[pxli168]

Summary

Fix the dump of PipeType.
Now we will have "pipe int" and element type.

[bader]

LGTM.
Probably it would be forth to add a simple test.

[Anastasia]

Do you think we could add a test? For example similar to test/Misc/ast-dump-decl.c. We could have it for now in test/SemaOpenCL folder.

[pxli168]

I will add a test and send a new version.

[pxli168]

Add test and fix some old test.

[yaxunl]

LGTM

[Anastasia]

LGTM! Thanks!

lib/AST/ASTDumper.cpp

void VisitObjCInterfaceType(const ObjCInterfaceType *T) {
       dumpDeclRef(T->getDecl());
     }
     void VisitObjCObjectPointerType(const ObjCObjectPointerType *T) {
       dumpTypeAsChild(T->getPointeeType());
     }
     void VisitAtomicType(const AtomicType *T) {
       dumpTypeAsChild(T->getValueType());
     }
+    void VisitPipeType(const PipeType *T) {
+      dumpTypeAsChild(T->getElementType());
+    }
     void VisitAdjustedType(const AdjustedType *T) {
       dumpTypeAsChild(T->getOriginalType());
     }
     void VisitPackExpansionType(const PackExpansionType *T) {
       if (auto N = T->getNumExpansions()) OS << " expansions " << *N;
       if (!T->isSugared())
         dumpTypeAsChild(T->getPattern());
     }

lib/AST/TypePrinter.cpp

void TypePrinter::printAtomicBefore(const AtomicType *T, raw_ostream &OS) {
   OS << ')';
   spaceBeforePlaceHolder(OS);
 }
 void TypePrinter::printAtomicAfter(const AtomicType *T, raw_ostream &OS) { }
 
 void TypePrinter::printPipeBefore(const PipeType *T, raw_ostream &OS) {
   IncludeStrongLifetimeRAII Strong(Policy);
 
-  OS << "pipe";
+  OS << "pipe ";
+  print(T->getElementType(), OS, StringRef());
   spaceBeforePlaceHolder(OS);
 }
 
 void TypePrinter::printPipeAfter(const PipeType *T, raw_ostream &OS) {
 }
 /// Appends the given scope to the end of a string.
 void TypePrinter::AppendScope(DeclContext *DC, raw_ostream &OS) {
   if (DC->isTranslationUnit()) return;