Apply only-Windows attribute to some path tests
Apply only-Windows attribute to some path tests

These tests touch Windows-only features like MAX_PATH and UNC paths, and
so shouldn't run on *nix.

cdmihai/msbuild,sean-gilliam/msbuild,sean-gilliam/msbuild,jeffkl/msbuild,rainersigwald/msbuild,mono/msbuild,chipitsine/msbuild,Microsoft/msbuild,cdmihai/msbuild,mono/msbuild,Microsoft/msbuild,jeffkl/msbuild,cdmihai/msbuild,Microsoft/msbuild,mono/msbuild,rainersigwald/msbuild,rainersigwald/msbuild,jeffkl/msbuild,jeffkl/msbuild,sean-gilliam/msbuild,mono/msbuild,cdmihai/msbuild,AndyGerlicher/msbuild,chipitsine/msbuild,AndyGerlicher/msbuild,rainersigwald/msbuild,AndyGerlicher/msbuild,AndyGerlicher/msbuild,chipitsine/msbuild,chipitsine/msbuild,Microsoft/msbuild,sean-gilliam/msbuild