gitlab: use 'setarch -R' to workaround tsan bug

gitlab: use 'setarch -R' to workaround tsan bug

The TSAN job started failing when gitlab rolled out their latest
release. The root cause is a change in the Google COS version used
on shared runners. This brings a kernel running with

 vm.mmap_rnd_bits = 31

which is incompatible with TSAN in LLVM < 18, which only supports
upto '28'. LLVM 18 can support upto '30', and failing that will
re-exec itself to turn off VA randomization.

Our LLVM is too old for now, but we can run with 'setarch -R make ..'
to turn off VA randomization ourselves.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-ID: <20240513111551.488088-4-berrange@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>