Fix all the code which has duplicate variable declarations

xfa/fxfa/fm2js/xfa_fmparse.cpp

 // Copyright 2014 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #include "xfa/fxfa/fm2js/xfa_fmparse.h"
 
 #include <memory>
 
@@ skipping 537 matching lines @@
     CXFA_FMSimpleExpression* e) {
   uint32_t line = m_pToken->m_uLinenum;
   while (1) {
     switch (m_pToken->m_type) {
       case TOKlparen: {
         NextToken();
         std::unique_ptr<CFX_ArrayTemplate<CXFA_FMSimpleExpression*>> pArray;
         if (m_pToken->m_type != TOKrparen) {
           pArray.reset(new CFX_ArrayTemplate<CXFA_FMSimpleExpression*>());
           while (m_pToken->m_type != TOKrparen) {
-            CXFA_FMSimpleExpression* e = ParseSimpleExpression();
-            if (e) {
-              pArray->Add(e);
-            }
+            if (CXFA_FMSimpleExpression* expr = ParseSimpleExpression())
+              pArray->Add(expr);
             if (m_pToken->m_type == TOKcomma) {
               NextToken();
             } else if (m_pToken->m_type == TOKeof ||
                        m_pToken->m_type == TOKreserver) {
               break;
             }
           }
           if (m_pToken->m_type != TOKrparen) {
             CFX_WideString ws_TempString(m_pToken->m_wstring);
             Error(m_pToken->m_uLinenum, kFMErrExpectedToken,
@@ skipping 470 matching lines @@
   NextToken();
   e.reset(ParseBlockExpression());
   Check(TOKend);
   if (m_pErrorInfo->message.IsEmpty()) {
     e.reset(new CXFA_FMDoExpression(line, e.release()));
   } else {
     e.reset();
   }
   return e.release();
 }