Add python_test_host module.

bug: 31676493
Test: created py_test modules in real folder. and ran 'mma'.
Change-Id: I22aa2fad74b11e4a31ea7a4c4a4f0ea64cd3fc94

python/library.go

@@ -37,7 +37,3 @@ func PythonLibraryHostFactory() (blueprint.Module, []interface{}) {
 
 	return InitPythonBaseModule(&module.pythonBaseModule, module, android.HostSupportedNoCross)
 }
-
-func (p *PythonLibrary) GeneratePythonAndroidMk() (ret android.AndroidMkData, err error) {
-	return
-}