Fix Windows CoreRun.exe to work with CoreCLR/Mono xplat hosting API. (#32788)

Fix Windows CoreRun.exe to work with CoreCLR/Mono xplat hosting API. (#32788)

CoreRun.exe is shared between both CoreCLR and Mono. On Windows,
CoreRun.exe is still using ICLRRuntimeHost4 hosting API but Mono
doesn't implement that API, just the xplat hosting API. Fix change
CoreRun.exe on Windows to use xplat hosting API, so it works with
both CoreCLR and Mono on Windows. CoreRun on Unix already used
xplat hosting API.

Behaviour on CoreRun.exe Windows CoreCLR should be identical, since
implementation of xplat hosting API on CoreCLR uses ICLRRuntimeHost4
internally and calls to CreateAppDomainWithManager, ExecuteAssembly,
UnloadAppDomain2 and Stop look identical to what done in CoreRun.exe
before this fix.