[clang][AST] Add get functions for CXXFoldExpr paren locations.

clang/include/clang/AST/ExprCXX.h

public:
   bool isLeftFold() const { return !isRightFold(); }
 
   /// Get the pattern, that is, the operand that contains an unexpanded pack.
   Expr *getPattern() const { return isLeftFold() ? getRHS() : getLHS(); }
 
   /// Get the operand that doesn't contain a pack, for a binary fold.
   Expr *getInit() const { return isLeftFold() ? getLHS() : getRHS(); }
 
+  SourceLocation getLParenLoc() const { return LParenLoc; }
+  SourceLocation getRParenLoc() const { return RParenLoc; }
   SourceLocation getEllipsisLoc() const { return EllipsisLoc; }
   BinaryOperatorKind getOperator() const { return Opcode; }
 
   Optional<unsigned> getNumExpansions() const {
     if (NumExpansions)
       return NumExpansions - 1;
     return None;
   }