ASSERT in api.static_signal test on Jenkins

Happened once in PR 5037: http://139.178.84.19:8080/job/DynamoRIO-AArch64-Precommit/698/consoleFull

232: ASSERT FAILURE: /var/lib/jenkins/workspace/DynamoRIO-AArch64-Precommit/suite/tests/api/static_signal.c:133: total > 0 ()