- Used pop instead of splice

and fix some eslint complaints

Implements changes suggested in pregmodfan/fc-pregmod!8659 (comment 142842) and pregmodfan/fc-pregmod!8659 (comment 142794)

Move slave-scoped temporary cross-report variables out of saVars and onto a proxy object, so they get reset automatically.

First time doing a PR to this, tell me if anything's wrong.