Better control of simplification and folding patterns via Pass Options

[GleasonK]

Request description

Per discussion in: #2586 (comment), we should consider what sorts of flags / options the simplification and folding pass should have.

Something like kFoldOpEltLimit should probably be controlled from the callsite, since some users will not want to fold at the expense of compile time, and others will want the smallest graph possible. And there are likely many other options like this i.e. OnlyFoldSplats.