Run Razor Toolset Tests

Pushes the current branch to dotnet/roslyn on GitHub and triggers the razor-toolset-ci Azure DevOps pipeline (definition 1270, project internal) to build the Razor compiler toolset and validate it against large third-party projects.

Background

The pipeline lives in the razor-toolset-tests repo in dnceng/internal. It:

1. Builds Microsoft.Net.Compilers.Razor.Toolset from the merged Roslyn repo
2. Injects it (plus the matching Roslyn toolset) into 11 third-party projects
3. Builds each project to verify compatibility

Projects tested: MudBlazor, Havit.Blazor, Telerik Blazor UI, OrchardCore, GrandNode2, Damselfly, Hawaso, dotnet-podcasts, and ASP.NET Core (MVC, Razor Pages, Blazor components).