Some improvements for the state package testing

[leolara]

What type of PR is this?

Refactor

What does this PR do? Why is it needed?

Avoids some code repetition in the state package testing

Which issues(s) does this PR fix?

Related #10047

Other notes for review

[terencechain]

Is there a particular reason snake case is preferred over camel case? Local IDE (Goland) complained about this

[leolara]

I am just copying what is the name of the original test: TestBeaconState_LatestBlockHeader

[terencechain]

Then I think camel case is preferred since this is no longer an executable test rather than a test only helper function

[leolara]

@terencechain please, check new commit

[rkapka]

Please also add state-native/v2/references_test.go and state-native/v3/references_test.go

[leolara]

@rkapka done

[rkapka]

Thanks! Let's wait for @terencechain's approval before merging

[rkapka]

bazel run //:gazelle -- fix needed

[rkapka]

Hey @leolara , I just checked daaa2f9 and I'm pretty sure what @terencechain meant was to change VerifyBeaconState_LatestBlockHeader to verifyBeaconStateLatestBlockHeader starting with a lowercase because it's a private helper function.

Found a small issue

[leolara]

@rkapka VerifyBeaconState_LatestBlockHeader or VerifyBeaconStateLatestBlockHeader cannot be private, it is called by the tests of the different state versions.

For example:

https://github.com/leolara/prysm/blob/testing/state_testing_coverage/beacon-chain/state/v1/getters_block_test.go#L12

Please let me know if you want the underscore in the name of the public VerifyBeaconState_... methods or you prefer VerifyBeaconState...

[rkapka]

Thanks for explaining. This looks good to me.