added performance benchmarks for FSM

[Aaronontheweb]

Fixes #2560

Changes

added performance benchmarks for FSM

Checklist

For significant changes, please ensure that the following have been completed (delete if not relevant):

• This change follows the Akka.NET API Compatibility Guidelines.
• This change follows the Akka.NET Wire Compatibility Guidelines.
• I have reviewed my own pull request.
• Design discussion issue Create a performance benchmark for FSM #2560

This PR's Benchmarks

BenchmarkDotNet=v0.13.1, OS=Windows 10.0.19044.2006 (21H2)
AMD Ryzen 7 1700, 1 CPU, 16 logical and 8 physical cores
.NET SDK=6.0.201
  [Host]     : .NET 6.0.3 (6.0.322.12309), X64 RyuJIT
  DefaultJob : .NET 6.0.3 (6.0.322.12309), X64 RyuJIT

Method	MsgCount	Mean	Error	StdDev	Ratio	RatioSD	Gen 0	Gen 1	Gen 2	Allocated
BenchmarkFsm	1000000	758.8 ms	10.92 ms	10.21 ms	1.67	0.03	69000.0000	4000.0000	1000.0000	287 MB
BenchmarkUntyped	1000000	456.2 ms	8.86 ms	10.21 ms	1.00	0.00	11000.0000	3000.0000	1000.0000	56 MB

LOTS of memory allocations for FSMs, and a 67% perf penalty.