tests/narrow-library.sh

tests: port test-simplekeyvaluefile.py to Python 3

# skip-blame just b prefixes

Differential Revision: https://phab.mercurial-scm.org/D3528

cat >> $HGRCPATH <<EOF
[extensions]
narrow=
[ui]
ssh=python "$TESTDIR/dummyssh"
[experimental]
changegroup3 = True
EOF