target/s390x: Handle branching to odd addresses

Let branching happen and try to generate a new translation block with
an odd address. Generate a specification exception in
cpu_get_tb_cpu_state().

Reported-by: Harold Grovesteen <h.grovsteen@tx.rr.com>
Reported-by: Nina Schoetterl-Glausch <nsg@linux.ibm.com>
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20230316164428.275147-2-iii@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>