Revert "[NFC] SimplifyCFGOptions: drop multi-parameter ctor, use default member-init"

This reverts commit 90c1b044.
This is based on another commit which also needs to be reverted.
The other commit introduced a Dependency Cycle between Transforms/Scalar
and TransformUtils. Scalar already depends (in many ways) on
TransformUtils, so making TransformUtils depend on Scalar should be
avoided.