update 08-probability.t to latest API's

Create a project programmatically instead of reading a directory.

Simply test that the correct number of `Result` objects were returned
instead of reading `amcpresults`.

Put the file in the AM test folder, since it tests the AM options.
update and move probability tests

Use the latest API (which reduces disk usage) in the probability
test, and move it into the AM folder since it tests an AM option.