remove excess dependency on RuntimeData classes.

Lots of code uses RuntimeData or ElementRuntimeData when it can get away with just DPathCompileInfo or DPathElementCompileInfo.

Cleaning this up will assist with DAFFODIL-1444. Unless things need the representational information, they don't need RuntimeData. E.g., expression compiling only needs DPathCompileInfo. Evaluatables only need DpathCompileInfo since they are about evaluatable expressions.