Gas price to substract to sender in up-front cost

[maximopalopoli]

Currently, in our evm implementation when we get the up-front cost from the sender, we get it using the max_fee_per_gas_or_gasprice function, which takes the max_fee_per_gas, and if there is none, the gas price is used. That is used here:

        // (1) GASLIMIT_PRICE_PRODUCT_OVERFLOW
        let gaslimit_price_product = self
            .max_fee_per_gas_or_gasprice()
            .checked_mul(self.env.gas_limit)
            .ok_or(VMError::TxValidation(
                TxValidationError::GasLimitPriceProductOverflow,
            ))?;

But, when returning the not consumed gas to the user, the max_fee_per_gas_or_gasprice function is not used but the gas price:

        let gas_return_amount = self
            .env
            .gas_price
            .low_u64()
            .checked_mul(gas_to_return)
            .ok_or(VMError::Internal(InternalError::UndefinedState(1)))?;

I tried to change this by using max_fee_per_gas_or_gasprice in the returning of the gas to the user but the change does not make pass more tests than before.

The test being debugged is coinbaseT2.json from the stEIP2930 folder. I also tried using gas_price instead of max_fee_per_gas_or_gasprice when substracting the up-front cost at the beggining, and that makes this and other tests pass, but in the overall there are less tests passing. The diff summary is the following:

Without the change:

stEIP1153-transientStorage: 0/8 (0.00%)
stExample: 8/12 (66.67%)
stEIP2930: 5/7 (71.43%)
eip4844_blobs: 229/559 (40.97%)


With the change: 

stEIP1153-transientStorage: 5/8 (62.50%)
stExample: 11/12 (91.67%)
stEIP2930: 6/7 (85.71%)
eip4844_blobs: 215/559 (38.46%)

[JereSalo]

Good issue