Remove obsolete Bazel spawn strategies

In I0a68895b57 obsolete Bazel spawn strategies were removed, but one
place was missed to be removed.

Change-Id: I7e0fe8dfbb075db416c7f3275e4eba271cbc51c4
diff --git a/jenkins/gerrit-bazel-build-plugin-branch.sh b/jenkins/gerrit-bazel-build-plugin-branch.sh
index d6662c2..7970e3f 100644
--- a/jenkins/gerrit-bazel-build-plugin-branch.sh
+++ b/jenkins/gerrit-bazel-build-plugin-branch.sh
@@ -31,8 +31,7 @@
 bazelisk version
 bazelisk build $BAZEL_OPTS $TARGETS
 
-BAZEL_OPTS="$BAZEL_OPTS --spawn_strategy=standalone --genrule_strategy=standalone \
-                   --test_output errors \
+BAZEL_OPTS="$BAZEL_OPTS --test_output errors \
                    --test_summary detailed --flaky_test_attempts 3 \
                    --test_verbose_timeout_warnings --build_tests_only \
                    --test_timeout 3600 \