Check if some auto apply code is dead and remove if appropriate.
There is a whole family of stg_ap_stk_* and stg_stk_save_* functions generated in AutoApply.cmm which as far as I can tell is not used anywhere in the compiler and can likely be removed.
In particular this would involve:
- Stop the code in question from being generated. (utils/genapply)
- Make sure that doesn't break things. (Validate/Run the testsuite).
- Grep for stk in the compiler to make sure we don't build calls to these in rare circumstances with string concatenation for extra safety.
- Document the change in patch notes just in case.