[CVE-2018-0778] Stack use after scope in Emit

The variable was declared inside an if-else condition and is used outside the block.

lib/Runtime/ByteCode/ByteCodeEmitter.cpp

@@ -11451,6 +11451,7 @@ void Emit(ParseNode *pnode, ByteCodeGenerator *byteCodeGenerator, FuncInfo *func
             }
         };
 
+        ByteCodeGenerator::TryScopeRecord tryRecForCatch(Js::OpCode::ResumeCatch, catchLabel);
         if (isPattern)
         {
             Parser::MapBindIdentifier(pnodeObj->sxParamPattern.pnode1, [&](ParseNodePtr item)
@@ -11471,7 +11472,6 @@ void Emit(ParseNode *pnode, ByteCodeGenerator *byteCodeGenerator, FuncInfo *func
             ParseNodePtr pnode1 = pnodeObj->sxParamPattern.pnode1;
             Assert(pnode1->IsPattern());
 
-            ByteCodeGenerator::TryScopeRecord tryRecForCatch(Js::OpCode::ResumeCatch, catchLabel);
             if (funcInfo->byteCodeFunction->IsCoroutine())
             {
                 byteCodeGenerator->tryScopeRecordsList.LinkToEnd(&tryRecForCatch);
@@ -11494,7 +11494,6 @@ void Emit(ParseNode *pnode, ByteCodeGenerator *byteCodeGenerator, FuncInfo *func
             byteCodeGenerator->Writer()->Empty(Js::OpCode::Nop);
             byteCodeGenerator->EndStatement(pnodeCatch);
 
-            ByteCodeGenerator::TryScopeRecord tryRecForCatch(Js::OpCode::ResumeCatch, catchLabel);
             if (funcInfo->byteCodeFunction->IsCoroutine())
             {
                 byteCodeGenerator->tryScopeRecordsList.LinkToEnd(&tryRecForCatch);