CI tests fail nondeterministically about half the time

[samalws-tob]

Tests will often fail but when you click "rerun failed tests" it succeeds the second time around

[samalws-tob]

The main failing test seems to be TestVerbosityLevels. It seems to fail because execution traces are getting assigned to the wrong transaction. Interestingly, data race detector finds a data race while running this test. (#269)

[dguido]

This appears related to #269 (tests fail with race detector). Both issues describe non-deterministic test failures.

Could this be a duplicate of #269, or are these separate flakiness issues? Would running go test -race ./... help confirm the root cause?