[#159730005] Add test to ensure buildpacks exist
[#159730005] Add test to ensure buildpacks exist

This will only catch borked installations for new environments but is
worth having anyway

@tlwr @jpluscplum

alphagov/paas-cf,alphagov/paas-cf,alphagov/paas-cf,alphagov/paas-cf,alphagov/paas-cf,alphagov/paas-cf,alphagov/paas-cf,alphagov/paas-cf