### Describe the bug, including details regarding any error messages, version, and platform. A wrong total_bytes to generate StringType's test data in vector_hash_benchmark. https://github.com/apache/arrow/blob/30e6d72242e376baa598b2e8f1d9b80d800a974c/cpp/src/arrow/compute/kernels/vector_hash_benchmark.cc#L128 It may cause the implicit buffer-overflow and inaccurate benchmark. ### Component(s) C++
Describe the bug, including details regarding any error messages, version, and platform.
A wrong total_bytes to generate StringType's test data in vector_hash_benchmark.
arrow/cpp/src/arrow/compute/kernels/vector_hash_benchmark.cc
Line 128 in 30e6d72
It may cause the implicit buffer-overflow and inaccurate benchmark.
Component(s)
C++