feat no invalidate reactive vars if dependencies are all static

[tanhauhau]

was looking at #4018 + playing around with the repl,

realise that if the dependencies of the reactive statements are static, there's no need to call $$invalidate.

[ghost]

EDIT: scratch all my previous comments as all the work is done compile time.

Anyways, I'd be worried about introducing a regression where something doesn't update when it should.

[stale]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[tanhauhau]

somehow the pipeline fails to install, even though it works locally