Add more tests for rewards

[cburgdorf]

What is wrong?

We recently added unit tests (additional to the existing state tests) that cover the rewards that are paid to the miners.

We should expand the following cases (citing from)

• calculating uncle/nephew reward when the uncle is on a different VM (like: uncle in frontier at 0, nephew in constantinople at 1)
• uncles that are 2 -> 8 layers back
• validating that uncles > 8 back are invalid

(I'm saying the last two without having reviewed the uncles section of the YP recently, so probably have some detail wrong)

How can it be fixed

Add test here

[pipermerriam]

Tests should be reasonably easy to write using the new chain builder tools and/or the fixture builder.

Fixture-builder would be ideal as we could potentially contribute those back upstream, but it's probably best to just start with chain-builder.

[Bhargavasomu]

I'm taking this up.

[Bhargavasomu]

This can be closed with #1685