[DFAJumpThreading] Investigate the appropriate position in pipeline

Currently, we place DFAJumpThreading in `PassBuilder::buildFunctionSimplificationPipeline`. But that may not be the best position to place this optimization. We may perform it as part of the optimization rather than the simplification pipeline, or we may perform it somewhere else in the pipeline. Anyway, we need to investigate its right place with evidence of runtime statistics and compile time statistics