Any objection to garbage collecting this?

This stopped being needed with the switch to generic_prepare_to_proceed
(nowadays prepare_to_proceed in infrun.c) a few years ago.

Tested on x86_64-unknown-linux-gnu, just in case.

I'm leaving the debug output that used it in place, in case
someone would miss it; just say so, and I'll zap it too.

-- 
Pedro Alves