Clean up tests by reusing functions from other modules:
Clean up tests by reusing functions from other modules:

* replace deltree with shutil.rmtree()
* replace mkdirs with os.makedirs()
* fold touchfile into GlobTests.mktemp()

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator