EIP-3855: PUSH0 instruction

[axic]

My hunch is that the majority of cases using the constant 1 are for-loops. And likely a large number of the uses of the constant 32 is for such loops too, which operate on word sizes. (Though a significant number of occurrences should be for memory operations.)

And for these use cases I think this is a better direction to go:

@axic

In fairness my hunch is that the constant 1 is mostly used for loops, in the form of PUSH1 1 ADD, so instead of that INC seems better. That is if we are willing to go into the direction of CISC. (PUSH0 is still inspired by the constant 0 register in RISC machines.)