testlib: Get rid of two_normalisers
And make normalise_fun polyvariadic. After all, this is untyped code, so
lets make use of it :-)
I think you need to call the testsuite and set the make var PYTHON as in
make PYTHON=python3 WAY=normal TESTS=...
But I didn't run the testsuite with Python3 myself yet... so this is mostly guesswork