This fixes the vast majority of test failures on HP NonStop.
Some test don't work with /bin/diff, some fail with /bin/tar,
so let's put /usr/local/bin in PATH first.
Some tests fail with /bin/sh (link to /bin/ksh) so use bash instead
Signed-off-by: Joachim Schmitz <jojo@schmitz-digital.de> Signed-off-by: Jeff King <peff@peff.net>