reduce synthesis search space

[KiaraGrouwstra]

size of the search space is a crucial aspect of synthesizer performance, but I may need to align this with the papers I'm benchmarking against, to ensure I'm not cheating on their tasks -- or vice versa, let them spend time searching for stuff (e.g. recursion) I never put in my task functions.

search space size mostly encompasses:

• the grammar -- e.g. leave out recursion (recursion #12), variables/lambdas (variables/lambdas #8)
• the building blocks -- basically these should match the functionality used to create the task functions, while preferably also being as generic as possible to get the most functionality using the smallest possible number of options.
• redundant patterns, e.g. only allow curried version of id (only relevant if my building blocks will include this function). note that Tamandu tackled this using a blacklist.