Basic snap support

[adamsitnik]

Fixes #1570

@AndreyAkinshin this is my last PR for 0.13.0

In the example below I have dotnet50 (snap) but no dotnet (typicall installation)

adam@adsitnik-ubuntu:~/projects/BenchmarkDotNet/samples/BenchmarkDotNet.Samples$ dotnet --info
bash: /usr/bin/dotnet: No such file or directory
adam@adsitnik-ubuntu:~/projects/BenchmarkDotNet/samples/BenchmarkDotNet.Samples$ dotnet50 run -c Release -f net5.0 --filter BenchmarkDotNet.Samples.IntroColdStart.Foo
/home/adam/projects/BenchmarkDotNet/src/BenchmarkDotNet/Attributes/Filters/OperatingSystemsArchitectureFilterAttribute.cs(15,96): warning CS1573: Parameter 'architectures' has no matching param tag in the XML comment for 'OperatingSystemsArchitectureFilterAttribute.OperatingSystemsArchitectureFilterAttribute(bool, params Architecture[])' (but other parameters do) [/home/adam/projects/BenchmarkDotNet/src/BenchmarkDotNet/BenchmarkDotNet.csproj]
/home/adam/projects/BenchmarkDotNet/src/BenchmarkDotNet/Attributes/Filters/OperatingSystemsFilterAttribute.cs(29,74): warning CS1573: Parameter 'platforms' has no matching param tag in the XML comment for 'OperatingSystemsFilterAttribute.OperatingSystemsFilterAttribute(bool, params OS[])' (but other parameters do) [/home/adam/projects/BenchmarkDotNet/src/BenchmarkDotNet/BenchmarkDotNet.csproj]
/home/adam/projects/BenchmarkDotNet/src/BenchmarkDotNet/Toolchains/DotNetCli/NetCoreAppSettings.cs(48,20): warning CS1573: Parameter 'customRuntimePack' has no matching param tag in the XML comment for 'NetCoreAppSettings.NetCoreAppSettings(string, string, string, string, string, TimeSpan?, string)' (but other parameters do) [/home/adam/projects/BenchmarkDotNet/src/BenchmarkDotNet/BenchmarkDotNet.csproj]
// Validating benchmarks:
// ***** BenchmarkRunner: Start   *****
// ***** Found 1 benchmark(s) in total *****
// ***** Building 1 exe(s) in Parallel: Start   *****
// start /snap/dotnet-sdk/112/dotnet restore  /p:UseSharedCompilation=false /p:BuildInParallel=false /m:1 /p:Deterministic=true /p:Optimize=true in /home/adam/projects/BenchmarkDotNet/samples/BenchmarkDotNet.Samples/bin/Release/net5.0/9a018ee4-0f33-46dd-9093-01d3bf31233b
// command took 1.49s and exited with 0
// start /snap/dotnet-sdk/112/dotnet build -c Release  --no-restore /p:UseSharedCompilation=false /p:BuildInParallel=false /m:1 /p:Deterministic=true /p:Optimize=true in /home/adam/projects/BenchmarkDotNet/samples/BenchmarkDotNet.Samples/bin/Release/net5.0/9a018ee4-0f33-46dd-9093-01d3bf31233b
// command took 2.78s and exited with 0
// ***** Done, took 00:00:04 (4.37 sec)   *****
// Found 1 benchmarks:
//   IntroColdStart.Foo: Job-NECTOD(IterationCount=5, RunStrategy=ColdStart)

// **************************
// Benchmark: IntroColdStart.Foo: Job-NECTOD(IterationCount=5, RunStrategy=ColdStart)
// *** Execute ***
// Launch: 1 / 1
// Execute: /snap/dotnet-sdk/112/dotnet "9a018ee4-0f33-46dd-9093-01d3bf31233b.dll" --benchmarkName "BenchmarkDotNet.Samples.IntroColdStart.Foo" --job "IterationCount=5, RunStrategy=ColdStart" --benchmarkId 0 in /home/adam/projects/BenchmarkDotNet/samples/BenchmarkDotNet.Samples/bin/Release/net5.0/9a018ee4-0f33-46dd-9093-01d3bf31233b/bin/Release/net5.0
Failed to set up high priority. Make sure you have the right permissions. Message: Permission denied
// BeforeAnythingElse

// Benchmark Process Environment Information:
// Runtime=.NET 5.0.3 (5.0.321.7212), X64 RyuJIT
// GC=Concurrent Workstation
// Job: Job-VYBEBI(IterationCount=5, RunStrategy=ColdStart)

// BeforeActualRun
// First call
WorkloadActual   1: 1 op, 1000798836.00 ns, 1.0008 s/op
WorkloadActual   2: 1 op, 10096348.00 ns, 10.0963 ms/op
WorkloadActual   3: 1 op, 10115168.00 ns, 10.1152 ms/op
WorkloadActual   4: 1 op, 10110514.00 ns, 10.1105 ms/op
WorkloadActual   5: 1 op, 10081318.00 ns, 10.0813 ms/op

// AfterActualRun
WorkloadResult   1: 1 op, 1000798836.00 ns, 1.0008 s/op
WorkloadResult   2: 1 op, 10096348.00 ns, 10.0963 ms/op
WorkloadResult   3: 1 op, 10115168.00 ns, 10.1152 ms/op
WorkloadResult   4: 1 op, 10110514.00 ns, 10.1105 ms/op
WorkloadResult   5: 1 op, 10081318.00 ns, 10.0813 ms/op

// AfterAll
// Benchmark Process 28019 has exited with code 0

Mean = 208.240 ms, StdErr = 198.140 ms (95.15%), N = 5, StdDev = 443.054 ms
Min = 10.081 ms, Q1 = 10.096 ms, Median = 10.111 ms, Q3 = 10.115 ms, Max = 1,000.799 ms
IQR = 0.019 ms, LowerFence = 10.068 ms, UpperFence = 10.143 ms
ConfidenceInterval = [-1,497.801 ms; 1,914.282 ms] (CI 99.9%), Margin = 1,706.042 ms (819.27% of Mean)
Skewness = 1.07, Kurtosis = 2.08, MValue = 2

// ***** BenchmarkRunner: Finish  *****

// * Export *
  BenchmarkDotNet.Artifacts/results/BenchmarkDotNet.Samples.IntroColdStart-report.csv
  BenchmarkDotNet.Artifacts/results/BenchmarkDotNet.Samples.IntroColdStart-report-github.md
  BenchmarkDotNet.Artifacts/results/BenchmarkDotNet.Samples.IntroColdStart-report.html

// * Detailed results *
IntroColdStart.Foo: Job-NECTOD(IterationCount=5, RunStrategy=ColdStart)
Runtime = .NET 5.0.3 (5.0.321.7212), X64 RyuJIT; GC = Concurrent Workstation
Mean = 208.240 ms, StdErr = 198.140 ms (95.15%), N = 5, StdDev = 443.054 ms
Min = 10.081 ms, Q1 = 10.096 ms, Median = 10.111 ms, Q3 = 10.115 ms, Max = 1,000.799 ms
IQR = 0.019 ms, LowerFence = 10.068 ms, UpperFence = 10.143 ms
ConfidenceInterval = [-1,497.801 ms; 1,914.282 ms] (CI 99.9%), Margin = 1,706.042 ms (819.27% of Mean)
Skewness = 1.07, Kurtosis = 2.08, MValue = 2
-------------------- Histogram --------------------
[-329.987 ms ;   350.166 ms) | @@@@
[ 350.166 ms ;   660.731 ms) | 
[ 660.731 ms ; 1,340.867 ms) | @
---------------------------------------------------

// * Summary *

BenchmarkDotNet=v0.12.1.20210220-develop, OS=ubuntu 18.04
Intel Xeon CPU E5-1650 v4 3.60GHz, 1 CPU, 12 logical and 6 physical cores
.NET SDK=5.0.103
  [Host]     : .NET 5.0.3 (5.0.321.7212), X64 RyuJIT
  Job-NECTOD : .NET 5.0.3 (5.0.321.7212), X64 RyuJIT

IterationCount=5  RunStrategy=ColdStart  

| Method |     Mean |      Error |   StdDev |   Median |      Min |        Max |
|------- |---------:|-----------:|---------:|---------:|---------:|-----------:|
|    Foo | 208.2 ms | 1,706.0 ms | 443.1 ms | 10.11 ms | 10.08 ms | 1,000.8 ms |

// * Warnings *
MinIterationTime
  IntroColdStart.Foo: IterationCount=5, RunStrategy=ColdStart -> The minimum observed iteration time is 10.0813 ms which is very small. It's recommended to increase it to at least 100.0000 ms using more operations.

// * Hints *
Outliers
  IntroColdStart.Foo: IterationCount=5, RunStrategy=ColdStart -> 1 outlier  was  detected (1.00 s)

// * Legends *
  Mean   : Arithmetic mean of all measurements
  Error  : Half of 99.9% confidence interval
  StdDev : Standard deviation of all measurements
  Median : Value separating the higher half of all measurements (50th percentile)
  Min    : Minimum
  Max    : Maximum
  1 ms   : 1 Millisecond (0.001 sec)

// ***** BenchmarkRunner: End *****
// ** Remained 0 benchmark(s) to run **
Run time: 00:00:01 (1.45 sec), executed benchmarks: 1

Global total time: 00:00:05 (5.83 sec), executed benchmarks: 1
// * Artifacts cleanup *