Share transitive closure calculation for TH splices in one shot mode

At the moment, in one shot mode, if you have TH splice, the entire transitive dependency is calculated each time you try to work out the dependencies for a splice.

This is slow and if you have many splices, a lot of redundant work happens. See test MultiLayerModulesTH_OneShot, and how much worse it is than MultiLayerModulesTH_Make.

Instead, we should store a module graph in the EPS and consult this to determine transitive dependencies in one shot mode.

Patch: !13753 (merged)