.gitlab-ci.d/crossbuilds.yml: Force 'make check' single-threaded for cross-i686-tci

The cross-i686-tci CI job is persistently flaky with various tests
hitting timeouts.  One theory for why this is happening is that we're
running too many tests in parallel and so sometimes a test gets
starved of CPU and isn't able to complete within the timeout.

(The environment this CI job runs in seems to cause us to default
to a parallelism of 9 in the main CI.)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-id: 20240912151003.2045031-1-peter.maydell@linaro.org

.gitlab-ci.d/crossbuilds.yml

@@ -62,7 +62,11 @@ cross-i686-tci:
     IMAGE: debian-i686-cross
     ACCEL: tcg-interpreter
     EXTRA_CONFIGURE_OPTS: --target-list=i386-softmmu,i386-linux-user,aarch64-softmmu,aarch64-linux-user,ppc-softmmu,ppc-linux-user --disable-plugins --disable-kvm
-    MAKE_CHECK_ARGS: check check-tcg
+    # Force tests to run in series, to see whether this
+    # reduces the flakiness of this CI job. The CI
+    # environment by default shows us 8 CPUs and so we
+    # would otherwise be using a parallelism of 9.
+    MAKE_CHECK_ARGS: check check-tcg -j1
 
 cross-mipsel-system:
   extends: .cross_system_build_job