CompareExchange_long benchmark sometimes reports very long execution time on x86

By looking at the data I got for x86 the `CompareExchange_long` benchmark typically reports time around `10ns`, but sometimes it's even `x100` more.

It's either a very weird hardware issue or a BenchmarkDotNet bug, possibly: https://github.com/dotnet/BenchmarkDotNet/issues/837

The problem is that I can't reproduce it locally... so if anyone ever faces this problem please copy-paste the content of BDN `.log` file here.

```cmd
git clone https://github.com/dotnet/performance.git
py .\performance\scripts\benchmarks_ci.py -f netcoreapp5.0 --filter System.Threading.Tests.Perf_Interlocked.CompareExchange_long --architecture x86
```