Allow forking blocks with future timestamps

[fvictorio]

If EDR forks a block whose timestamp is in "the future", then it panics with an error like this:

thread 'tokio-runtime-worker' panicked at /build/crates/edr_provider/src/data.rs:2564:18:
current time must be after fork block: SystemTimeError(3340.313588137s)

The easiest way to reproduce this manually is to just set the system clock back one hour and then fork mainnet.

I don't see any good reason to disallow this and, as far as I can tell, pre-EDR Hardhat didn't have this behavior.

See zemse/hardhat-tracer#74 (comment) for more context.