gitlab-ci.yml: Add jobs to test CFI flags

QEMU has had options to enable control-flow integrity features
for a few months now. Add two sets of build/check/acceptance
jobs to ensure the binary produced is working fine.

The three sets allow testing of x86_64 binaries for x86_64, s390x,
ppc64 and aarch64 targets

[AJB: tweak job names to avoid brands]

Signed-off-by: Daniele Buono <dbuono@linux.vnet.ibm.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20210304030948.9367-3-dbuono@linux.vnet.ibm.com>
Message-Id: <20210305092328.31792-9-alex.bennee@linaro.org>