Call setreuid and setregid in a subprocess to avoid altering the test runner's process state.  Should fix issue8045.
Call setreuid and setregid in a subprocess to avoid altering the test runner's
process state.  Should fix issue8045.

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