Revert "[clang] - Add missing builtin name to AtomicExpr JSON dump"

This reverts commit dbccf3c.

The test added is failing on many bots including:
- https://lab.llvm.org/buildbot/#/builders/164/builds/42716
- https://lab.llvm.org/buildbot/#/builders/188/builds/34429
- https://lab.llvm.org/buildbot/#/builders/245/builds/13103
- https://lab.llvm.org/buildbot/#/builders/258/builds/6002
- https://lab.llvm.org/buildbot/#/builders/230/builds/17690
- https://lab.llvm.org/buildbot/#/builders/91/builds/17722
- https://lab.llvm.org/buildbot/#/builders/67/builds/12466
- https://lab.llvm.org/buildbot/#/builders/109/builds/72108
- https://lab.llvm.org/buildbot/#/builders/139/builds/48265
- https://lab.llvm.org/buildbot/#/builders/216/builds/26208
- https://lab.llvm.org/buildbot/#/builders/36/builds/36964
- https://lab.llvm.org/buildbot/#/builders/247/builds/8222

Author: dyung

clang/include/clang/AST/Expr.h

@@ -6480,15 +6480,6 @@ class AtomicExpr : public Expr {
   QualType getValueType() const;
 
   AtomicOp getOp() const { return Op; }
-  StringRef getOpAsString() const {
-    switch (Op) {
-#define BUILTIN(ID, TYPE, ATTRS)
-#define ATOMIC_BUILTIN(ID, TYPE, ATTRS)                                        \
-  case AO##ID:                                                                 \
-    return #ID;
-#include "clang/Basic/Builtins.def"
-    }
-  }
   unsigned getNumSubExprs() const { return NumSubExprs; }
 
   Expr **getSubExprs() { return reinterpret_cast<Expr **>(SubExprs); }

clang/include/clang/AST/JSONNodeDumper.h

@@ -285,7 +285,6 @@ class JSONNodeDumper
   void VisitBinaryOperator(const BinaryOperator *BO);
   void VisitCompoundAssignOperator(const CompoundAssignOperator *CAO);
   void VisitMemberExpr(const MemberExpr *ME);
-  void VisitAtomicExpr(const AtomicExpr *AE);
   void VisitCXXNewExpr(const CXXNewExpr *NE);
   void VisitCXXDeleteExpr(const CXXDeleteExpr *DE);
   void VisitCXXThisExpr(const CXXThisExpr *TE);

clang/lib/AST/JSONNodeDumper.cpp

@@ -1179,10 +1179,6 @@ void JSONNodeDumper::VisitBlockDecl(const BlockDecl *D) {
   attributeOnlyIfTrue("capturesThis", D->capturesCXXThis());
 }
 
-void JSONNodeDumper::VisitAtomicExpr(const AtomicExpr *AE) {
-  JOS.attribute("name", AE->getOpAsString());
-}
-
 void JSONNodeDumper::VisitObjCEncodeExpr(const ObjCEncodeExpr *OEE) {
   JOS.attribute("encodedType", createQualType(OEE->getEncodedType()));
 }