Fix OOB memory access in JSON reader ingest_raw utility

[davidwendt]

Description

Fixes out-of-bounds memory reads in the JSON reader ingest_raw internal utility.
Error found in the nightly memcheck and can be reproduced using:

compute-sanitizer --tool memcheck gtests/JSON_TEST --gtest_filter=JsonReaderTest/JsonReaderTest.ByteRange_MultiSource/0 --rmm_mode=cuda

Error reported:

========= COMPUTE-SANITIZER
Note: Google Test filter = JsonReaderTest/JsonReaderTest.ByteRange_MultiSource/0
[==========] Running 1 test from 1 test suite.
[----------] Global test environment set-up.
[----------] 1 test from JsonReaderTest/JsonReaderTest
[ RUN      ] JsonReaderTest/JsonReaderTest.ByteRange_MultiSource/0
========= Program hit cudaErrorInvalidValue (error 1) due to "invalid argument" on CUDA API call to cudaMemcpyAsync_ptsz.
=========     Saved host backtrace up to driver entry point at error
=========         Host Frame: cudf::io::json::detail::ingest_raw_input(cudf::device_span<char, 18446744073709551615ul>, cudf::host_span<std::unique_ptr<cudf::io::datasource, std::default_delete<cudf::io::datasource> >, 18446744073709551615ul>, unsigned long, unsigned long, char, rmm::cuda_stream_view) [0xd51b19] in libcudf.so
=========         Host Frame: std::vector<cudf::io::table_with_metadata, std::allocator<cudf::io::table_with_metadata> > split_byte_range_reading<int>(cudf::host_span<std::unique_ptr<cudf::io::datasource, std::default_delete<cudf::io::datasource> >, 18446744073709551615ul>, cudf::host_span<std::unique_ptr<cudf::io::datasource, std::default_delete<cudf::io::datasource> >, 18446744073709551615ul>, cudf::io::json_reader_options const&, cudf::io::json_reader_options const&, int, rmm::cuda_stream_view, rmm::detail::cccl_async_resource_ref<cuda::mr::__4::basic_resource_ref<(cuda::mr::__4::_AllocType)1, cuda::mr::__4::device_accessible> >) [0x1bd7a1] in JSON_TEST
...

The cudaMemcpyAsync call was writing past the end of the allocated device memory buffer.

Once this was fixed, another error appears reading past the end of the buffer returned by ingest_raw.
This is fixed by clamping the returned size to at most the size of the device buffer itself.

Checklist

• I am familiar with the Contributing Guidelines.
• New or existing tests cover these changes.
• The documentation is up to date with these changes.

[shrshi]

The OOB error was in the chunking logic in the tests. We had not taken into account the newlines between files. So the size allocated by the buffer in

cudf/cpp/tests/io/json/json_utils.cuh

Line 42 in 27abc1d

rmm::device_uvector<char> buffer(total_source_size, stream);

was off by the number of source files.

[davidwendt]

/merge