Describe the bug, including details regarding any error messages, version, and platform.

Some of the decimal benchmarks access their benchmark data in strides, without checking that the accesses fall withing bounds. Example here, where kValueSize (10) is actually not a multiple of 4:

This manifests in crashes on some of the macOS benchmark machines, and the issue can be reproduced locally using Valgrind:

$ ARROW_DEFAULT_MEMORY_POOL=system valgrind <build dir>/relwithdebinfo/arrow-decimal-benchmark --benchmark_repetitions=6 --benchmark_min_time=0.050000s

Component(s)

C++