* testsuite/ld-elf/linux-x86.exp: Build tests when non-native.
(check_pr25749b): Add optional args. Set expected pass file
from args. Run -1b and -2a tests with passall.out.
* testsuite/ld-elf/passall.out: New file.
* testsuite/ld-elf/pr25749-1.c: Adjust to pass with older glibc.
* testsuite/ld-elf/pr25749-2.c: Likewise.
* testsuite/lib/ld-lib.exp (run_ld_link_exec_tests): Use
regexp_diff to compare expected output from running binary.