When mixing linkonce and comdat sections, we need to keep searching to
get the real kept section.
bfd/
PR ld/26936
* elflink.c (_bfd_elf_check_kept_section): Get the real kept
section.
ld/
PR ld/26936
* testsuite/ld-elf/pr26936.d: New file.
* testsuite/ld-elf/pr26936a.s: Likewise.
* testsuite/ld-elf/pr26936b.s: Likewise.
* testsuite/ld-elf/pr26936c.s: Likewise.
