tests/tcg/s390x: Enable the multiarch system tests

tests/tcg/s390x: Enable the multiarch system tests

Multiarch tests are written in C and need support for printing
characters. Instead of implementing the runtime from scratch, just
reuse the pc-bios/s390-ccw one.

Run tests with -nographic in order to enable SCLP (enable this for
the existing tests as well, since it does not hurt).

Use the default linker script for the new tests.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20230511114651.439872-3-iii@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>