itest: increase mempool timeout

Neutrino can get slow towards the end of the itests.

lntest/timeouts.go

@@ -7,7 +7,7 @@ import "time"
 const (
 	// MinerMempoolTimeout is the max time we will wait for a transaction
 	// to propagate to the mining node's mempool.
-	MinerMempoolTimeout = time.Second * 30
+	MinerMempoolTimeout = time.Minute
 
 	// ChannelOpenTimeout is the max time we will wait before a channel to
 	// be considered opened.

lntest/timeouts_darwin.go

@@ -7,7 +7,7 @@ import "time"
 const (
 	// MinerMempoolTimeout is the max time we will wait for a transaction
 	// to propagate to the mining node's mempool.
-	MinerMempoolTimeout = time.Second * 30
+	MinerMempoolTimeout = time.Minute
 
 	// ChannelOpenTimeout is the max time we will wait before a channel to
 	// be considered opened.