[llvm] [BOLT] Allow missing DT_FINI{,_ARRAY} if instrumentation-sleep-time is used (PR #170086)

[Vasily Leonenko via llvm-commits]

vleonen wrote:

> Nit: suggestion for shortening/clarity of the commit message subject:
> 
> > [BOLT] Allow missing DT_FINI{,_ARRAY} if instrumentation-sleep-time is used
> 
> The implementation otherwise looks reasonable to me. Please wait at least 24h to give others a chance to chime in before submitting.
> 
> I note that some well known workloads call `_exit` and can skip the exit hooks anyway, as well. So anyone working with those and using instrumentation-sleep-time would already be experiencing 'counters not flushed at the end of the workload' in the same way.

Thank you for review. I updated PR description based on your recommendations.

https://github.com/llvm/llvm-project/pull/170086