Fix integer overflow

[ 63%] Building CXX object main/native/libhdfspp/tests/CMakeFiles/hdfs_ext_hdfspp_test_shim_static.dir/hdfs_ext_test.cc.o
In file included from /mnt/d/projects/apache/hadoop/hadoop-hdfs-project/hadoop-hdfs-native-client/src/out/build/WSL-GCC-Debug/main/native/libhdfspp/googletest-src/googletest/include/gtest/gtest.h:375,
                 from /mnt/d/projects/apache/hadoop/hadoop-hdfs-project/hadoop-hdfs-native-client/src/out/build/WSL-GCC-Debug/main/native/libhdfspp/googletest-src/googlemock/include/gmock/internal/gmock-internal-utils.h:47,
                 from /mnt/d/projects/apache/hadoop/hadoop-hdfs-project/hadoop-hdfs-native-client/src/out/build/WSL-GCC-Debug/main/native/libhdfspp/googletest-src/googlemock/include/gmock/gmock-actions.h:51,
                 from /mnt/d/projects/apache/hadoop/hadoop-hdfs-project/hadoop-hdfs-native-client/src/out/build/WSL-GCC-Debug/main/native/libhdfspp/googletest-src/googlemock/include/gmock/gmock.h:59,
                 from /mnt/d/projects/apache/hadoop/hadoop-hdfs-project/hadoop-hdfs-native-client/src/main/native/libhdfspp/tests/hdfspp_mini_dfs.h:24,
                 from /mnt/d/projects/apache/hadoop/hadoop-hdfs-project/hadoop-hdfs-native-client/src/main/native/libhdfspp/tests/hdfs_ext_test.cc:19:
/mnt/d/projects/apache/hadoop/hadoop-hdfs-project/hadoop-hdfs-native-client/src/main/native/libhdfspp/tests/hdfs_ext_test.cc: In member function ‘virtual void hdfs::HdfsExtTest_TestHosts_Test::TestBody()’:
/mnt/d/projects/apache/hadoop/hadoop-hdfs-project/hadoop-hdfs-native-client/src/main/native/libhdfspp/tests/hdfs_ext_test.cc:456:95: warning: integer overflow in expression of type ‘long int’ results in ‘-9223372036854775808’ [-Woverflow]
  456 |   EXPECT_EQ(nullptr, hdfsGetHosts(fs, filename.c_str(), 0, std::numeric_limits<int64_t>::max()+1));
      |                                                            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~
/mnt/d/projects/apache/hadoop/hadoop-hdfs-project/hadoop-hdfs-native-client/src/main/native/libhdfspp/tests/hdfs_ext_test.cc:460:92: warning: integer overflow in expression of type ‘long int’ results in ‘-9223372036854775808’ [-Woverflow]
  460 |   EXPECT_EQ(nullptr, hdfsGetHosts(fs, filename.c_str(), std::numeric_limits<int64_t>::max()+1, std::numeric_limits<int64_t>::max()));
      |                                                         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~