UT IOSignalTest.mixedSignals fails under Ubuntu 22.04 VMs
I have Ubuntu 22.04 VMs under macOS and Ubuntu 22.04 hosts and IOSignalTest.mixedSignals fails intermittently under both VMs. Signal arrival order cannot be guaranteed so it is possible for the test to hit the expected stop count of 8 signals but not have the expected number of each type of signal (i.e. 8 total, but not the right mix). I've attached a simple diff that makes it reliable.