This modifies the tests that deal serializing the Invoice type to limit
the creation date to seconds since Go1.9 added the concept of a
monotonic component to times which does not round trip through
MarshalBinary and UnmarshalBinary and therefore causes the tests to fail.
In particular, it modifies the creation dates in the randInvoice,
makeFakePayment, makeRandomFakePayment, and TestInvoiceWorkflow
functions.
This results in allowing TestOutgoingPaymentSerialization,
TestOutgoingPaymentWorkflow, and TestInvoiceWorkflow to pass.
This corrects the fuzz test in TestLightningWireProtocol for
MsgCommitSig to avoid creating an empty slice since the decoded message
only creates a slice when there are greater than zero signatures and an
empty slice is not considered equal to a nil slice under reflection.
This can be tested by running the TestLightningWireProtocol 1000 times
in a loop with and without this change.