SignalR: Fix Crankier build (#9976)

* fix benchmarkapps build
* move Directory.* to BenchmarkServer

Author: staff0rd

src/SignalR/perf/benchmarkapps/Directory.Build.props renamed to src/SignalR/perf/benchmarkapps/BenchmarkServer/Directory.Build.props

@@ -33,7 +33,7 @@ public void ConfigureServices(IServiceCollection services)
             }
         }
 
-        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
+        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
         {
             app.UseSignalR(routes =>
             {