itest+lntest: add itest for mempool preimage watch

itest/list_on_test.go

@@ -523,4 +523,12 @@ var allTestCases = []*lntest.TestCase{
 		Name:     "channel fundmax",
 		TestFunc: testChannelFundMax,
 	},
+	{
+		Name:     "htlc timeout resolver extract preimage remote",
+		TestFunc: testHtlcTimeoutResolverExtractPreimageRemote,
+	},
+	{
+		Name:     "htlc timeout resolver extract preimage local",
+		TestFunc: testHtlcTimeoutResolverExtractPreimageLocal,
+	},
 }