.oniro-ci: set toolchain to gcc and runtime to gun for gcc tests

Signed-off-by: Chase Qi <chase.qi@linaro.org>

.oniro-ci/build-generic.yaml

@@ -481,6 +481,8 @@
     MACHINE: qemux86-64
     CI_ONIRO_BUILD_FLAVOUR: linux
     CI_ONIRO_BB_LOCAL_CONF_SANITY_TESTED_DISTROS: ""
+    CI_ONIRO_BB_LOCAL_CONF_TOOLCHAIN: "gcc"
+    CI_ONIRO_BB_LOCAL_CONF_RUNTIME: "gnu"
     CI_ONIRO_OE_SELFTESTS: ""
     CI_ONIRO_OE_SEFLTEST_SKIPS: ""
     CI_SQUAD_INSTANCE: "https://squadp.svc.ostc-eu.dev"