sweep: account for all script types in craftSweepTx

With this change, transactions created via craftSweepTx will be
standard. Previously, p2wsh/p2pkh scripts passed in via SendCoins would
be weighted as p2wpkh scripts. With a feerate of 1 sat/vbyte,
transactions returned would be non-standard. Luckily, the critical
sweeper subsystem only used p2wpkh scripts so this only affected
callers from the rpcserver.

Also added is an integration test that fails if SendCoins manages
to generate a non-standard transaction. All script types are now
accounted for in getWeightEstimate, which now errors if an unknown
script type is passed in.

sweep/weight_estimator.go

@@ -83,6 +83,12 @@ func (w *weightEstimator) addP2TROutput() {
 	w.estimator.AddP2TROutput()
 }
 
+// addP2WSHOutput updates the weight estimate to account for an additional
+// segwit v0 P2WSH output.
+func (w *weightEstimator) addP2WSHOutput() {
+	w.estimator.AddP2WSHOutput()
+}
+
 // addOutput updates the weight estimate to account for the known
 // output given.
 func (w *weightEstimator) addOutput(txOut *wire.TxOut) {