test: skip non-Windows tests if on Windows
test: skip non-Windows tests if on Windows

bradking/ninja,sgraham/ninja,maruel/ninja,bradking/ninja,ninja-build/ninja,ninja-build/ninja,Qix-/ninja,sgraham/ninja,ninja-build/ninja,AoD314/ninja,bradking/ninja,Qix-/ninja,AoD314/ninja,maruel/ninja,iwadon/ninja,iwadon/ninja,bradking/ninja,AoD314/ninja,sgraham/ninja,ninja-build/ninja,maruel/ninja,maruel/ninja,AoD314/ninja,sgraham/ninja,Qix-/ninja,iwadon/ninja,Qix-/ninja,iwadon/ninja