Squashed 'native/sylvan/' changes from aae9dd5..eaafc34

eaafc34 Improved sylvan_test
84e47bb Some improvements to llmsset randomisation
7757ed5 Bugfix error on Mac

git-subtree-dir: native/sylvan
git-subtree-split: eaafc349992266241a0993d11cf44626f66c5214
Update Sylvan to latest version