all: simplify timestamps to uint64 (#19372)

* all: simplify timestamps to uint64

* tests: update definitions

* clef, faucet, mobile: leftover uint64 fixups

* ethash: fix tests

* graphql: update schema for timestamp

* ethash: remove unused variable

miner/worker.go

@@ -828,8 +828,8 @@ func (w *worker) commitNewWork(interrupt *int32, noempty bool, timestamp int64)
 	tstart := time.Now()
 	parent := w.chain.CurrentBlock()
 
-	if parent.Time().Cmp(new(big.Int).SetInt64(timestamp)) >= 0 {
-		timestamp = parent.Time().Int64() + 1
+	if parent.Time() >= uint64(timestamp) {
+		timestamp = int64(parent.Time() + 1)
 	}
 	// this will ensure we're not going off too far in the future
 	if now := time.Now().Unix(); timestamp > now+1 {
@@ -844,7 +844,7 @@ func (w *worker) commitNewWork(interrupt *int32, noempty bool, timestamp int64)
 		Number:     num.Add(num, common.Big1),
 		GasLimit:   core.CalcGasLimit(parent, w.gasFloor, w.gasCeil),
 		Extra:      w.extra,
-		Time:       big.NewInt(timestamp),
+		Time:       uint64(timestamp),
 	}
 	// Only set the coinbase if our consensus engine is running (avoid spurious block rewards)
 	if w.isRunning() {