simulators/ethereum/engine: Transition Payload checks

[marioevz]

This PR adds checks on the transition tests, specifically to verify the return values of the Engine API endpoints on:

• newPayload(TP) where TP is a valid transition payload built on top of a valid terminal block.
• forkchoiceUpdated(TB) where TB is a valid terminal block.
• newPayload(INV_TP) where INV_TP is an invalid payload built on top of a terminal block where TB.Parent.TD >= TTD
• newPayload(INV_TP) where INV_TP is an invalid payload built on top of a terminal block where TB.TD < TTD
• forkchoiceUpdated(INV_TB) where INV_TB.Parent.TD >= TTD
• forkchoiceUpdated(INV_TB) where INV_TB.TD < TTD

These changes improve on previous tests where the only passing requirement was that the client didn't switch to the invalid chain. Here the INVALID response to the CL must be verified.

cc @mkalinin

[mkalinin]

LGTM! 👍

[marioevz]

I removed the Terminal Block checks from this PR due to this:
It's not possible to have an fcU(INV_TB) where the invalid terminal block is also unknown to the EL, that would mean that the CL is getting information from other EL, which is not possible with current configurations.

Test case where fcU(INV_TB) && INV_TB.TD < TTD, which could occur due to a misconfiguration of the CL, will be added in a separate PR.

I also reduced TimeoutSeconds for the original test case variants from 3 minutes to the default 1 minute.