[BUG] `compute-sanitizer` shows a lot of uninitialized read errors in `write_orc`

[ttnghia]

When running compute-sanitizer --tool initcheck on ORC_TEST, I observed a lot of errors like this:

========= Host API memory access error at host access to 0x77cfa2a7dc00 of size 3,840 bytes
=========     Uninitialized access to 0x77cfa2a7dce0 on access by cudaMemcpy source
=========     Saved host backtrace up to driver entry point at error
=========         Host Frame: cudaMemcpyAsync_ptsz [0x2e90bc] in ORC_TEST
=========         Host Frame: cudf::detail::cuda_memcpy_async_impl(void*, void const*, unsigned long, cudf::detail::host_memory_kind, rmm::cuda_stream_view) [0x8409f5] in ORC_TEST
=========         Host Frame: cudf::io::orc::detail::(anonymous namespace)::allocate_and_encode_blobs(cudf::detail::hostdevice_vector<cudf::io::statistics_merge_group>&, cudf::device_span<cudf::io::statistics_chunk const, 18446744073709551615ul>, int, rmm::cuda_stream_view) [0x530952] in ORC_TEST
=========         Host Frame: cudf::io::orc::detail::(anonymous namespace)::gather_statistic_blobs(cudf::io::statistics_freq, cudf::io::orc::detail::orc_table_view const&, cudf::io::orc::detail::file_segmentation const&, rmm::cuda_stream_view) [0x531bde] in ORC_TEST
=========         Host Frame: cudf::io::orc::detail::(anonymous namespace)::convert_table_to_orc_data(cudf::table_view const&, cudf::io::table_input_metadata const&, cudf::io::orc::detail::stripe_size_limits, int, bool, bool, cudf::io::compression_type, unsigned long, cudf::io::statistics_freq, bool, cudf::io::detail::single_write_mode, cudf::io::data_sink const&, rmm::cuda_stream_view) [0x5405a2] in ORC_TEST
=========         Host Frame: cudf::io::orc::detail::writer::impl::write(cudf::table_view const&) [0x541510] in ORC_TEST
=========         Host Frame: cudf::io::write_orc(cudf::io::orc_writer_options const&, rmm::cuda_stream_view) [0x4bb6ce] in ORC_TEST
=========         Host Frame: (anonymous namespace)::write_file(std::vector<std::unique_ptr<cudf::column, std::default_delete<cudf::column> >, std::allocator<std::unique_ptr<cudf::column, std::default_delete<cudf::column> > > >&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, bool, unsigned long, int) [0x1b4069] in ORC_TEST
=========         Host Frame: OrcChunkedReaderTest_TestChunkedReadSimpleData_Test::TestBody()::{lambda(bool, unsigned long)#1}::operator()(bool, unsigned long) const [clone .isra.0] [0x1b8e3a] in ORC_TEST
=========         Host Frame: OrcChunkedReaderTest_TestChunkedReadSimpleData_Test::TestBody() [0x1bd7fe] in ORC_TEST
=========         Host Frame: void testing::internal::HandleExceptionsInMethodIfSupported<testing::Test, void>(testing::Test*, void (testing::Test::*)(), char const*) [0x34f7cc] in ORC_TEST
=========         Host Frame: testing::Test::Run() [0x33e55d] in ORC_TEST
=========         Host Frame: testing::TestInfo::Run() [0x33e6e4] in ORC_TEST
=========         Host Frame: testing::TestSuite::Run() [0x33e8de] in ORC_TEST
=========         Host Frame: testing::internal::UnitTestImpl::RunAllTests() [0x347953] in ORC_TEST
=========         Host Frame: testing::UnitTest::Run() [0x347d34] in ORC_TEST
=========         Host Frame: main [0xcb98d] in ORC_TEST