Bound env variables (NUMBER, TIMESTAMP) by reasonable values

[palinatolmach]

Currently, environmental variables such as block.number and block.timestamp are symbolic and are only bounded by the type range constraints. We can further restrict their values by adding some reasonable bounds, e.g., #rangeUInt(32, NUMBER) for block.number, which is ~3 orders of magnitude larger that current block number, as suggested by @ehildenb.

[lucasmt]

I have PR #2277 open to add bounds to the block.timestamp variable, and block.number is already bounded here. But from what I understand this issue is proposing to have stricter bounds for them based on what values we can reasonably expect these variables to have. Is this still something we want?

[anvacaru]

I'd say to merge it as it is. We can further constrain block.number if we see fit.

[palinatolmach]

Moving it into backlog for it to be addressed if/when we run into this issue. As suggested by @lucasmt, an alternative is to use vm.assume to provide bounds on the value, e.g., vm.assume(block.number < 65536);.