all: make timestamp-based fork checks based on uint64 (#26474)

This PR changes the API so that uint64 is used for fork timestamps.
It's a good choice because types.Header also uses uint64 for time.

Co-authored-by: Felix Lange <fjl@twurst.com>

cmd/evm/internal/t8ntool/execution.go

@@ -138,7 +138,7 @@ func (pre *Prestate) Apply(vmConfig vm.Config, chainConfig *params.ChainConfig,
 		Transfer:    core.Transfer,
 		Coinbase:    pre.Env.Coinbase,
 		BlockNumber: new(big.Int).SetUint64(pre.Env.Number),
-		Time:        new(big.Int).SetUint64(pre.Env.Timestamp),
+		Time:        pre.Env.Timestamp,
 		Difficulty:  pre.Env.Difficulty,
 		GasLimit:    pre.Env.GasLimit,
 		GetHash:     getHash,