it does not already exist.
* ld.bootstrap/bootstrap.exp: Don't create tmpdir here.
* ld.cdtest/cdtest.exp: Likewise.
* ld.scripts/defined.exp: Likewise. Also, don't set as and nm
here. Change perror for no variables found to fail.
* ld.scripts/script.exp: New test.
* ld.scripts/script.t, ld.scripts/script.s: New files.
