Recognize more targets as ELF for testing

Also use the correct rel strip-13 variant for more ARM targets.

	* testsuite/lib/binutils-common.exp (is_elf_format): Add chorus,
	cloudabi, fuchsia, kaos and nto.  Merge netbsdelf* into *elf*,
	and *uclinux* into *linux*.
	* testsuite/binutils-all/objcopy.exp: Accept armeb for rel
	strip-13 test, exclude arm-vxworks and arm-windiss.