Fix TypeInitializationException for WebHostBuilder

[lmolkova]

System.TypeInitializationException : The type initializer for 'Microsoft.ApplicationInsights.AspNetCore.DiagnosticListeners.HostingDiagnosticListener' threw an exception.
---- System.TypeLoadException : Method 'ConfigureAppConfiguration' in type 'Microsoft.AspNetCore.Hosting.WebHostBuilder' from assembly 'Microsoft.AspNetCore.Hosting, Version=1.0.2.0, Culture=neutral, PublicKeyToken=adb9793829ddae60' does not have an implementation.
   at Microsoft.ApplicationInsights.AspNetCore.DiagnosticListeners.HostingDiagnosticListener.Dispose()
   at Microsoft.ApplicationInsights.AspNetCore.RequestTrackingTelemetryModule.Dispose(Boolean disposing)

HostingDiagnosticListener uses WebHostBuilder class to determine Asp.NET Core version. Base IWebHostBuilder interface is loaded from Microsoft.AspNetCore.Hosting.Abstractions while WebHostBuilder is defined in Microsoft.AspNetCore.Hosting.
AppInsights SDK reference Ms.AspNetCore.Hosting 1.0.2.

In AspNetCore 2.0 timeframe, a new interface method ConfigureAppConfiguration was added to IWebHostBuilder, which 1.0.2 does not implement.

If user app does reference abstractions of relevant version (2.0+), but not hosting, the base interface has ConfigureAppConfiguration while implementation AppInsights brings in 1.0.2 does not implement it which causes this error.

This is the case in WebJobs.

This change determines AspNetCore version based on IWebHodstBuilder to avoid issues like this.

It also changes how we test HostingDiagnosticListener, allowing to parametrize aspnetcore version and test different combinations.

[cijothomas]

chaneglog