bug: gas values taken from the stack should be a u256s

[enitrat]

Bug Report

Even if this is an unreasonable assumption that a transaction could be sent with an amount of gas > 2**128, internally, the gas is not bound to be smaller than a u128.

As such, one could send a CALL instruction where gas = max(u256). Of course, the gas passed to the call would be bounded to the gas_left of the execution, but it means that if the gas passed to a call is >2**128, the call should still be executed, and the tx should not revert when executing the CALL opcode.