Fix disabled Eth1Block test

[paulhauner]

Description

As per #1765 (comment), we need to resolve this:

lighthouse/testing/ef_tests/tests/tests.rs

Lines 193 to 194 in 2eced35

	// FIXME(sproul): move Eth1Block to consensus/types
	// ssz_static_test!(eth1_block, Eth1Block);

Notes

• Only valid once [Merged by Bors] - Update to spec v1.0.0-rc.0 and BLSv4 #1765 is merged.
• Will conflict with VC GUI: required information #1691, probably best to wait until its merged.

[michaelsproul]

I'm removing this FIXME in #2279 because I don't think that test is relevant to us. The Eth1Block from the spec is a loosely defined object, and our Eth1Block has two more fields than it:

lighthouse/common/eth2/src/lighthouse.rs

Lines 173 to 181 in b34a79d

	/// A block of the eth1 chain.
	#[derive(Debug, PartialEq, Clone, Serialize, Deserialize, Encode, Decode)]
	pub struct Eth1Block {
	pub hash: Hash256,
	pub timestamp: u64,
	pub number: u64,
	pub deposit_root: Option<Hash256>,
	pub deposit_count: Option<u64>,
	}

[michaelsproul]

Same reasoning applies to new merge type PowBlock.