3.0.1. SigmaP review. Not emit events on _transfer() when balanceIncrease == 0

[eboadom]

Context

Regarding #701

aave-v3-core/contracts/protocol/tokenization/base/ScaledBalanceTokenBase.sol

Lines 157 to 158 in 84b900c

	emit Transfer(address(0), sender, senderBalanceIncrease);
	emit Mint(_msgSender(), sender, senderBalanceIncrease, senderBalanceIncrease, index);

When balanceIncrease() == 0, it probably doesn't make sense to emit the events, given that they are done for accounting consistency, not going against the ERC20 standard.
Additionally, it is not consistent to have different behaviour for sender and recipient