Build ifunc tests when non-native
Plus a number of fixes to the pr23169 tests.
* testsuite/lib/ld-lib.exp (check_ifunc_available): Pass without
running executable when non-native.
(check_ifunc_attribute_available): Likewise.
* testsuite/ld-ifunc/pr23169a.rd: Remove extraneous lines. Match
st_other strings. Pass when func is an ifunc.
* testsuite/ld-ifunc/pr23169b.rd: Remove extraneous lines. Correct
reloc regexp. Correct match-anything line.
* testsuite/ld-ifunc/pr23169c.rd: Remove extraneous lines. Match
st_other strings.