XFA: Fix win8 gn build under chromium checkout (non-xfa)

third_party/bigint/BigIntegerUtils.cc

 // 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 by Matt McCutchen, see the LICENSE file.
 
 #include "BigIntegerUtils.hh"
 #include "BigUnsignedInABase.hh"
 
 std::string bigUnsignedToString(const BigUnsigned &x) {
@@ skipping 25 matching lines @@
         else if (osFlags & os.hex) {
                 base = 16;
                 if (osFlags & os.showbase)
                         os << "0x";
         } else if (osFlags & os.oct) {
                 base = 8;
                 if (osFlags & os.showbase)
                         os << '0';
         } else
         abort();
+
         std::string s = std::string(BigUnsignedInABase(x, base));
         os << s;
         return os;
 }
 
 std::ostream &operator <<(std::ostream &os, const BigInteger &x) {
         if (x.getSign() == BigInteger::negative)
                 os << '-';
         os << x.getMagnitude();
         return os;
 }