stay in double to avoid overflow

CoinUtils/src/CoinFactorization4.cpp:2290:42: runtime error: 2.28294e+09 is
outside the range of representable values of type 'int'

Author: christoph-cullmann

src/CoinFactorization4.cpp

@@ -2287,7 +2287,7 @@ void CoinFactorization::updateColumnTransposeL(CoinIndexedVector *regionSparse)
   // we may need to rethink on dense
   if (sparseThreshold_ > 0) {
     if (btranAverageAfterL_) {
-      int newNumber = static_cast< int >(number * btranAverageAfterL_);
+      double newNumber = number * btranAverageAfterL_;
       if (newNumber < sparseThreshold_)
         goSparse = 2;
       else if (newNumber < sparseThreshold2_)