Update .NET 9 runtime for single machine CI job

[jjonescz]

Fixes this error in the single machine CI leg (which runs only in main branch):

Testhost process for source(s) 'D:\a\_work\1\s\artifacts\bin\Roslyn.Compilers.VisualBasic.IOperation.UnitTests\Debug\net9.0\Roslyn.Compilers.VisualBasic.IOperation.UnitTests.dll' exited with error: You must install or update .NET to run this application.
App: D:\a\_work\1\s\artifacts\bin\Roslyn.Compilers.VisualBasic.IOperation.UnitTests\Debug\net9.0\testhost.exe
Architecture: x64
Framework: 'Microsoft.NETCore.App', version '9.0.0-rc.2.24473.5' (x64)
.NET location: D:\a\_work\1\s\.dotnet
The following frameworks were found:
  9.0.0-preview.3.24172.9 at [D:\a\_work\1\s\.dotnet\shared\Microsoft.NETCore.App]
Learn more:
https://aka.ms/dotnet/app-launch-failed
To install missing framework, download:
https://aka.ms/dotnet-core-applaunch?framework=Microsoft.NETCore.App&framework_version=9.0.0-rc.2.24473.5&arch=x64&rid=win-x64&os=win10
. Please check the diagnostic logs for more information.
Test Run Aborted.

[RikkiGibson]

Man I wish it were more straightforward to flow the sdk version from global.json here. This is obviously prone to fall out of date, but, I'm not sure we can justify the investigation effort at this point either.

[RikkiGibson]

There is a useGlobalJson task parameter but surely no use if global.json is not on disk on the test machine.

[jjonescz]

Good point, I might look into this later (perhaps when arcade bumps SDK and I will need to do this again). But for now, the tests are actually failing on some assert, so I'm going to prioritize investigating that.

[jjonescz]

@sharwell @tmat it looks like the test Microsoft.CodeAnalysis.UnitTests.Interactive.InteractiveHostDesktopTests.Bitness fails when calling InteractiveHost.Reset. The failure is from here:

roslyn/src/Interactive/HostTest/AbstractInteractiveHostTests.cs

Line 65 in 3bc2a12

Assert.False(true, (exception?.Message ?? "Host process terminated unexpectedly.") + $" Exit code: {exitCode?.ToString() ?? "<unknown>"}");

And it only fails on the Single_Machine leg. There aren't any details about the error. Any ideas what to do about it?

The last build where it worked is https://dev.azure.com/dnceng-public/public/_build/results?buildId=866953. It was running on a machine with .NET runtime 9.0.0-preview.3.24172.9 and VS 17.11.0 Preview 2.1. Then the CI machine updated to VS 17.12.0 Preview 4 it seems and so I needed to update the .NET runtime to 9.0.100-rc.2.24474.11 (see the error in this PR's description).