Expand MSBuildSdkResolver

[surayya-MS]

Fixes dotnet/msbuild#11086

Context

Details - Here's the flow for sdk resolution in msbuild repo
MSBuildSdkResolver is in resolver list only in case of msbuild.exe.
MSBuildSdkResolver is not present in case of dotnet build. Hence, Muxer is not available in msbuild.exe context as the corresponding issue description suggests.

Changes

1. Added DOTNET_HOST_PATH to the SdkResult.PropertiesToAdd with value of the path of dotnet.exe similar to dotnet CLI does before triggering builds
2. Added SdkResolverMSBuildTaskHostRuntimeVersion to the SdkResult.PropertiesToAdd with value of the runtime version MSBuild uses (from MSBuild.runtimeconfig.json file) similar to Muxer.SharedFxVersion

Testing

Manually tested by building sdk repo with build.cmd, then copying Microsoft.DotNet.MSBuildSdkResolver.dll to msbuild, then running msbuild.exe on a console app. Result - DOTNET_HOST_PATH and SdkResolverMSBuildTaskHostRuntimeVersion are present in the binlog as a property in Evaluation phase.
Added check for DOTNET_HOST_PATH and SdkResolverMSBuildTaskHostRuntimeVersion keys in unit tests.

[baronfel]

When this is merged, we will want to backport to release/9.0.2xx so that this will ship in a version of VS that Roslyn can use to begin testing. If we don't backport, they would have to wait until we had an insertion of .NET 10 into VS, which is quite a while away.

[surayya-MS]

/backport to release/9.0.2xx

[github-actions]

Started backporting to release/9.0.2xx: https://github.com/dotnet/sdk/actions/runs/12323103032