don't compile generators which have yields optimized away (fixes test_collections)
don't compile generators which have yields optimized away (fixes test_collections)

brettcannon/Pyjion,brettcannon/Pyjion,DinoV/Pyjion-1,Microsoft/Pyjion,Microsoft/Pyjion,DinoV/Pyjion-1,DinoV/Pyjion-1,DinoV/Pyjion-1,brettcannon/Pyjion,Microsoft/Pyjion,Microsoft/Pyjion