Add a new consolidation test & two new pending deposit tests

[jtraglia]

This PR will:

• Fix a few small nits (variable names, function names, spacing, punctuation).
• Add test_basic_consolidation_source_has_less_than_max_effective_balance -- a test where the source validator (with 0x01 creds) has an effective balance with less than 32 ETH. This shouldn't prevent the consolidation.
• Add test_apply_pending_deposit_over_min_activation_next_increment -- a test where the deposit amount is 33 ETH. There's an existing test with a deposit amount of 32 ETH + 1 Gwei, but that only ensures the client mod's with the effective balance increment. It wouldn't catch a client that forgets to compare with the max effective balance.
• Add test_apply_pending_deposit_compounding_withdrawal_credentials_over_max_next_increment -- a test like the previous one, but it's a compounding validator and the values are bigger: 2049 ETH.

[mkalinin]

LGTM!