Remove TargetLatestRuntimePatch properties

[Evangelink]

Description

Looking at history and after discussion in the team, it seems that this was added only to allow CheckEolTargetFramework that wasn't supported on older patches.

[nohwnd]

Cool. This will also make #3968 work more reliably.

For future reference: The reason why using TargetLatestRuntimePatch is not desirable, is that this will force the runtimeconfig.json of testhost and other executables we produce to specify the latest version that the SDK we built with knows about (from the file mentioned in the comment "tools\dotnet\sdk<version from global json>\Microsoft.NETCoreSdk.BundledVersions.props" instead of using 3.1.xx for netcoreapp3.1, and 6.0.xx for net6 (etc.), no matter which sdk we built with. Forcing the higher version makes our executables less portable, and makes it more difficult to setup the CI machine.