Flaky tests due to special values being treated differently by Jaeger

[janstenpickle]

Because we use Scalacheck to generate test data for the Jaeger round trip, sometimes data that gets treated specially by Jaeger gets generated, so the resulting response isn't in the format we expect causing a test failure.

Thinking about what is being tested, i.e. the ability to send data to Jaeger, we don't really need to test that Jaeger can accept any randomly generated data, just that the data gets sent correctly via different exporters. Given this, we should have some pre-generated data tables that we know Jaeger won't mangle or treat as special cases.