* Make `dotnet msbuild` the default on Windows too
- add step using desktop `msbuild` when native builds may be involved
- `-All` (without `-NoBuildNative`), `-BuildNative` or `-BuildInstallers` run this step
- but `-ForceCoreMsbuild` unconditionally skips this step
nits:
- add binary log for RepoTasks build if `$BinaryLog` (echoes the `dotnet msbuild` command)
- add blank lines between build steps
* Enable building managed projects depending on native assets
- splitting native builds out confuses these projects
- use `$(BuildNative)` less, only to control actual building (not bundling)
- build both native platforms in one `msbuild` invocation
* Adjust generation scripts to explicitly choose the MSBuild engine
- ensure native assets are included in GenerateReferenceAssemblies.ps1 build
- clean up the global state that tools.ps1 corrupts
* Revert move to VS2019.Pre queues
This reverts part of commit b67d161e03
- was "[release/5.0-preview5] Update dependencies from dotnet/aspnetcore-tooling (#21710)"
* Revert "!temporary! Require `msbuild` from VS2019 16.6"
- this reverts commit 58cf2304a6
* Reduce build duplication in pipelines
- build native assets and repo tasks once per CI job
- only cleanup framework references after packing managed projects
nits:
- wrap a few long lines
- remove extra `-forceCoreMsbuild` options in SiteExtensions' build.cmd
* Fix Helix jobs
- restore.cmd doesn't work well with `-projects`; script unconditionally adds `-all`
* !fixup! Reduce duplications further
- missed a couple of places `-noBuildRepoTasks` helps
* Cleanup: Remove a few dangling binary logs
* !fixup! Correct typos in generation scripts
* !fixup! Another typo in the generation scripts