pe.em and pep.em make_import_fixup

This is a little cleanup that I made when looking at pr30343 that
makes it more obvious that make_import_fixup in both files are
identical (and in fact the new pep.em read_addend could be used in
both files).

	* emultempl/pep.em (read_addend): Extract from..
	(make_import_fixup): ..here.
	* emultempl/pe.em (read_addend): Similarly.
	(make_import_fixup): Similarly.  Add debug code from pep.em.