add -Pslf4j2x to native ci, so it gets slf4j dep for compiling.

Author: zhumin8

.kokoro/build.sh

@@ -80,14 +80,14 @@ graalvmA)
     # Run Unit and Integration Tests with Native Image
     bash .kokoro/populate-secrets.sh
     export GOOGLE_APPLICATION_CREDENTIALS="${KOKORO_GFILE_DIR}/secret_manager/java-it-service-account"
-    mvn -B ${INTEGRATION_TEST_ARGS} -ntp -Pnative -Pnative-test test -pl 'oauth2_http'
+    mvn -B ${INTEGRATION_TEST_ARGS} -ntp -Pnative -Pnative-test -Pslf4j2x test -pl 'oauth2_http'
     RETURN_CODE=$?
     ;;
 graalvmB)
     # Run Unit and Integration Tests with Native Image
     bash .kokoro/populate-secrets.sh
     export GOOGLE_APPLICATION_CREDENTIALS="${KOKORO_GFILE_DIR}/secret_manager/java-it-service-account"
-    mvn -B ${INTEGRATION_TEST_ARGS} -ntp -Pnative -Pnative-test test -pl 'oauth2_http'
+    mvn -B ${INTEGRATION_TEST_ARGS} -ntp -Pnative -Pnative-test -Pslf4j2x test -pl 'oauth2_http'
     RETURN_CODE=$?
     ;;
 samples)