Consider ways to build singlefilehost as a part of coreclr partition build

[VSadov]

Building singlefilehost as a part of installer requires 300-400 corclr_static library, which results in extra 80Mb transferred to the consuming partition as a part of artifacts zip file.

(for details see: #36847 (comment))

There could be ways to build singlefilehost as a part of coreclr, which would make the lib unnecessary. It could be either a cross-partition build like used by native components of System.Globalization and up to separating hosting parts of the installer partition and moving over to coreclr.

[VSadov]

fixed in #48254