qt/test/apptests.cpp fails on Xenial, likely due to a race condition
as we do not see this behavior on Buster. This behavior appears to be fixed by
backporting PR15101 but has many dependencies (see T697). Until PR15101 is backported,
this will provide a quick bandaid so that developers working on Xenial machines can continue working.
The failure case for this is that payment server slots/signals are not correctly connected. Depending on how the race condition manifests in the wild, bitcoin-qt may fail for BIP70 payments. I expect this to be low user impact considering
the few users using the wallet software, and the fewer who use it for BIP70 payments.