ci: Avoid subshell for executing HWCI_TEST_SCRIPT

Ensure that $HWCI_TEST_SCRIPT is an executable we can run ourselves, and
run that directly instead of invoking a subshell.

Signed-off-by: Daniel Stone <daniels@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/31110>

.gitlab-ci/common/generate-env.sh

@@ -64,6 +64,7 @@ VARS=(
     HWCI_KVM
     HWCI_START_WESTON
     HWCI_START_XORG
+    HWCI_TEST_ARGS
     HWCI_TEST_SCRIPT
     IR3_SHADER_DEBUG
     JOB_ARTIFACTS_BASE

.gitlab-ci/common/init-stage2.sh

@@ -201,7 +201,7 @@ if [ -n "$HWCI_START_WESTON" ]; then
 fi
 
 set +e
-bash -c ". $SCRIPTS_DIR/setup-test-env.sh && $HWCI_TEST_SCRIPT"
+$HWCI_TEST_SCRIPT ${HWCI_TEST_ARGS:-}
 EXIT_CODE=$?
 set -e