test: ensure tests convert from BTC to SAT properly

This commit is a follow up to the prior commit which fixed a rounding
error bug in lnwallet. For uniformity, we also fix other occurrences in
the breach arbiter, as well as the integration tests.

breacharbiter_test.go

@@ -1255,7 +1255,11 @@ func createInitChannels(revocationWindow int) (*lnwallet.LightningChannel, *lnwa
 	bobKeyPriv, bobKeyPub := btcec.PrivKeyFromBytes(btcec.S256(),
 		bobsPrivKey)
 
-	channelCapacity := btcutil.Amount(10 * 1e8)
+	channelCapacity, err := btcutil.NewAmount(10)
+	if err != nil {
+		return nil, nil, nil, err
+	}
+
 	channelBal := channelCapacity / 2
 	aliceDustLimit := btcutil.Amount(200)
 	bobDustLimit := btcutil.Amount(1300)