[mono] Disable using `resgen.exe` on mono completely
[mono] Disable using `resgen.exe` on mono completely

This was disabled by default on msbuild, but only for >v3.5 projects.
This disables it completely. The reason being that mono's `resgen` is
not complete and doesn't support some command line args like `/r:` for
references.

mono/msbuild,mono/msbuild,mono/msbuild,mono/msbuild