In this commit, we modify the way we detect local force closes. Before
this commit, we would directly check the broadcast commitment's txid
against what we know to be our best local commitment. In the case of DLP
recovery from an SCB, it's possible that the user force closed, _then_
attempted to recover their channels. As a result, we need to check the
outputs directly in order to also handle this rare, but
possible recovery scenario.
The new detection method uses the outputs to detect if it's a local
commitment or not. Based on the state number, we'll re-derive the
expected scripts, and check to see if they're on the commitment. If not,
then we know it's a remote force close. A new test has been added to
exercise this new behavior, ensuring we catch local closes where we have
and don't have a direct output.
In this commit, we speed up the `TestChainWatcherDataLossProtect`
_considerably_ by enumerating relevant tests using table driven tests
rather than generating random tests via the `testing/quick` package.
Each of these test cases are also run in parallel bringing down the
execution time of this test from a few minutes, to a few seconds.
In this commit, we add a new test case to exercise the way we handle the
DLP detection and dispatch within the chain watcher. Briefly, we use
the `testing/quick` package to ensure that the following invariant is
always held: "if we do N state updates, then state M is broadcast, iff M
> N, we'll execute the DLP protocol". We limit the number of iterations
to 10 for now, as the tests can take a bit of time to execute, since it
actually does proper state transitions.
