[master] Update dependencies from dotnet/arcade dotnet/aspnetcore-tooling (#21630)

* Update dependencies from https://github.com/dotnet/arcade build 20200511.9
- Microsoft.DotNet.Arcade.Sdk: 5.0.0-beta.20228.4 => 5.0.0-beta.20261.9
- Microsoft.DotNet.GenAPI: 5.0.0-beta.20228.4 => 5.0.0-beta.20261.9
- Microsoft.DotNet.Helix.Sdk: 5.0.0-beta.20228.4 => 5.0.0-beta.20261.9

* Update dependencies from https://github.com/dotnet/aspnetcore-tooling

 build 20200514.6

Microsoft.AspNetCore.Mvc.Razor.Extensions , Microsoft.AspNetCore.Razor.Language , Microsoft.CodeAnalysis.Razor , Microsoft.NET.Sdk.Razor
 From Version 5.0.0-preview.5.20261.4 -> To Version 5.0.0-preview.6.20264.6

* Pre-emptively take -nobl change

* Disable binlogs in CI

* Fix build.sh to know about -nobl

* Align build.ps1|sh with latest Arcade parameters
- do not enable binary logs by default in CI builds
- leave `-binaryLog` and `-excludeCIBinaryLog` handling to eng/common/tools.ps1|sh
  - was unnecessary since `-bl /bl:{some name}` worked fine, ignoring OOMs

nit: document `-excludeCIBinarylog` a bit more

* Do not pass unknown options into CodeCheck.ps1

* Pass `-ci -nobl` into remaining CI build jobs

* Switch default TFM to `net5.0`

* Update missing project templates tfms

* Add more `-ci -nobl`
- needed because _all_ builds in the pipeline are implicitly CI builds
  - default-build.yml adds `-ci` when script wasn't explicit

* Default templates to net5.0

* PR feedback

* Update TFMs in explicit .nuspec files

* Update TFMs in test projects

* Update TFMs in test C# code

* Update TFMs in infrastructure files

* Future-proof a check for `net5.0` or later
- avoid comparisons involving `$(TargetFramework)` in .targets files
  - fine to compare it with `''` or `$(DefaultNetCoreTargetFramework)`

* !fixup! Undo a couple of earlier fixes
- remove a duplicate `$()` setting
- correct the one remaining versioned `#if` define
  - did not make it `#if NETCOREAPP` because benchmarks test numerous .NET Core TFMs

* Disable binary logs in CodeCheck.ps1

* Specify `-ci -nobl` just once when using `parameters.buildArgs`

* Restore `$binaryLog` default logic

Co-authored-by: Doug Bunting <6431421+dougbu@users.noreply.github.com>
Co-authored-by: Will Godbe <wigodbe@microsoft.com>
Co-authored-by: Viktor Hofer <viktor.hofer@microsoft.com>