Test all Coder structuralValue implementations

Here is a test helper that check that structuralValue is consistent with equals: https://github.com/apache/beam/blob/master/sdks/java/core/src/main/java/org/apache/beam/sdk/testing/CoderProperties.java#L200

And here is one that tests it another way: https://github.com/apache/beam/blob/master/sdks/java/core/src/main/java/org/apache/beam/sdk/testing/CoderProperties.java#L226

With the deprecation of consistentWithEquals and implementing all the structualValue methods, we should add these tests to every coder.

Imported from Jira [BEAM-6904](https://issues.apache.org/jira/browse/BEAM-6904). Original Jira may contain additional context.
Reported by: kenn.