testsuite: do not fail on systems without read permissions. * tests/instfail-info.test: Do not use the `non-root' requirement for testing whether files may be made unreadable; instead use `test -r' and skip the test if that still works. * tests/instfail-java.test: Likewise. * tests/instfail-libtool.test: Likewise. * tests/instfail.test: Likewise. * tests/instmany-mans.test: Likewise. * tests/instmany-python.test: Likewise. * tests/instmany.test: Likewise. * tests/parallel-tests9.test: Likewise. Signed-off-by: Ralf Wildenhues <Ralf.Wildenhues@gmx.de>