Remove CPP ensuring word size is 32 or 64 bits around Addr# <-> int# primops

It shouldn't be needed these days, and those primops are "highly deprecated" anyways.

This fits with my plans because it removes one bit of target-dependence of the builtin primops, and this is the hardest part of GHC to make multi-target.

Progress towards #11470

CC @carter

• are either individually buildable or squashed
• have commit messages which describe what they do (referring to Notes and tickets using #NNNN syntax when appropriate)
• have added source comments describing your change. For larger changes you likely should add a Note and cross-reference it from the relevant places.
• add a testcase to the testsuite.
• if your MR affects library interfaces (e.g. changes base) please add the ~"user facing" label.

If you have any questions don't hesitate to open your merge request and inquire in a comment. If your patch isn't quite done yet please do add prefix your MR title with WIP:.