[flang] Remove AbstractConverter usages from the Optimizer library

It seems some usages of AbstractConverter crept in in the Optimizer library in
https://github.com/llvm/llvm-project/commit/00769d69fbaa39ecdcbbaf826a35ad999bdc951e.

The Optimizer libraries are not meant to depend on data structure from Lower to avoid cycles. Beside, the AbstractConverter.h is pulling a lot of expensive headers. Propagate the needed options instead of using the converter directly.

Start by reviewing commit 00769d69fbaa39ecdcbbaf826a35ad999bdc951e and locating AbstractConverter usages in the Optimizer libraries. Trace which options each usage needs and identify how they can be propagated without depending on Lower data structures. Done means the Optimizer libraries no longer use AbstractConverter directly.

Written by the indexing model from the issue text.