folding.rcp: upstream moved to github

also remove needless :features, set hooks in :prepare to support lazy
mode.
shorten set_default
reuse code from test-utils.sh
test-utils.sh: only use funcname() syntax

function keyword is redundant
refactor test_recipe into test-utils.sh
refactor run_test into test-utils.sh
refactor common parts of test_recipe and run_test