Fixed the build

- csc kept crashing on stage 2 and it turned out to be a version mismatch with System.Reflection.Metadata.
- Silenced crossgen
- Made omnisharp see all of the projects

scripts/dotnet-cli-build/CompileTargets.cs

@@ -356,7 +356,7 @@ namespace Microsoft.DotNet.Cli.Build
             foreach (var assemblyToCrossgen in AssembliesToCrossGen)
             {
                 c.Info($"Crossgenning {assemblyToCrossgen}");
-                ExecIn(outputDir, crossgen, "-nologo", "-platform_assemblies_paths", outputDir, assemblyToCrossgen);
+                ExecInSilent(outputDir, crossgen, "-nologo", "-platform_assemblies_paths", outputDir, assemblyToCrossgen);
             }
 
             c.Info("Crossgen complete");