Add Visual Stido 2019 to Windows runners

Windows builds for [rules_foreign_cc](https://github.com/bazelbuild/rules_foreign_cc) seem to be having issues on windows. A recent PR (https://github.com/bazelbuild/rules_foreign_cc/pull/757) runs into issues in [this build](https://buildkite.com/bazel/rules-foreign-cc/builds/3407#d2da4c9e-ee60-48f4-bc5e-64160b431ad1):
```
CMake Error at CMakeLists.txt:3 (project):
Generator

Visual Studio 15 2017

could not find any instance of Visual Studio.
```

And by trying to update to a newer version Visual Studio (https://github.com/bazelbuild/rules_foreign_cc/pull/758) [CI shows](https://buildkite.com/bazel/rules-foreign-cc/builds/3408#4852aa57-a4bf-4b8d-8148-7407eb19d6ae):
```
CMake Error at CMakeLists.txt:6 (project):
Generator

Visual Studio 16 2019

could not find any instance of Visual Studio.
```

It'd be nice if a recent version of visual studio was installed. But I'll settle for whatever fixes CI 😄

No repository files or tests are named. Start with the linked Buildkite failures and compare PRs #757 and #758 to identify the Windows runner configuration involved. Done means the selected Visual Studio generator is installed or otherwise supported and the affected Windows CI build passes.

Written by the indexing model from the issue text.