Hi!
This PR tries to fix Dapper.Performance.Tests, actually you can't get [MemoryDiagnoser](https://benchmarkdotnet.org/api/BenchmarkDotNet.Diagnosers.MemoryDiagnoser.html)  stats because 
```IDiagnoser.GetColumnProvider()``` method was gone on BenchmarkDotnet 0.11.2. I choose ```DefaultColumnProviders.Metrics``` because of [this](https://github.com/dotnet/BenchmarkDotNet/issues/1184#issuecomment-507377695), i think it's the most simple way to add stats now.

**Before**
![image](https://user-images.githubusercontent.com/34173061/65264060-1a5f7780-db0e-11e9-9c8c-bb4c69a808df.png)

**After**
![image](https://user-images.githubusercontent.com/34173061/65264158-4f6bca00-db0e-11e9-9313-597b09070ae6.png)

On the other hand i choose removing ```[Ordered]``` as temporal solution of https://github.com/dotnet/BenchmarkDotNet/issues/1238, and yeah, the results are still ordered because of https://github.com/StackExchange/Dapper/blob/9282ef2872e1c82c68c86f31e93e8f1ceaacd409/Dapper.Tests.Performance/Config.cs#L42

**Before**
![image](https://user-images.githubusercontent.com/34173061/65264660-6232ce80-db0f-11e9-9046-9c2d8fc5e2d8.png)

**After**
 (No errors)

Thanks for all!!