Write tests for the following cases

[jchittoda]

Scenarios to test:

• 1. simple small liquidation
• 1.1 USDC collateral, ETH debt
• 1.2 ETH collateral, USDC debt
• 2. simple big liquidation - three liquidators
• 2.1 USDC collateral, ETH debt
• 2.2 ETH collateral, USDC debt
• 3. Liquidations in chunk (repeat 1 and 2)
• 4. partial liquidation, followed by user operation (that reset it), and then another liquidation (with different collateral)
• 4.1. partial liquidation, followed by user operation (that reset it), and then another liquidation (with different debt)
• 5. full liquidation, then another liquiation for the same debt, then another liquiation for different debt
• 5. topup to a small debt, then increasing the debt, and let another liquidator top it up
• 6. topup to a big debt, then debt becomes smaller, and another liquidator topup
• 7. topup to debt A, user repay, and then topup to debt B
• 8. untop
• 9. liquidate on compound directly, and via B. compare the liquidator (+jar) get the same
• 10. test get account liquiditiy by reading it from compound directly, then do topup, and then read it from B. Should get the same result. Do the same tests for get borrrow balance.