ignore ExitStatus exceptions in node toplevel, and add force_exit test; fixes #2629
return NULL from setlocale for bad locales; fixes #2630
be careful with loop helpers, any of them may require a looptemp, not just the one matching the loop var, due to substitution of them all at once; fixes a regression from 398cded47b7e08fbb753fb7b4788da29a22195bb ; fixes #2626