target/s390x: Fix EXECUTE of relative long instructions

target/s390x: Fix EXECUTE of relative long instructions

The code uses the wrong base for relative addressing: it should use the
target instruction address and not the EXECUTE's address.

Fix by storing the target instruction address in the new CPUS390XState
member and loading it from the code generated by gen_ri2().

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>
Reviewed-by: David Hildenbrand <david@redhat.com>
Message-Id: <20230316210751.302423-2-iii@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
(cherry picked from commit 703d03a4aaf38f285555ef5422ba5ce075416fc4)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>