testsuite: also try `jot' as `seq' replacement. * tests/instmany-mans.test: Try BSD `jot' before resorting to a slow but portable shell loop. * tests/instmany-python.test: Likewise. * tests/instmany.test: Likewise. Suggestion by Peter O'Gorman. Signed-off-by: Ralf Wildenhues <Ralf.Wildenhues@gmx.de>