This commit removes the context as a param needed when calling methods
of HarnessNode. This change moves the context management inside
HarnessNode, aside from saving us a few lines, it makes the context
creation/timeout less error-prone.
In this commit, we put the context initialization inside
openChannelAndAssert, thus saving us a few lines and making sure the
context is always properly handled.
This commit adds a test for a hold invoice which is accepted
off-chain, and held by the recipient until it expired and
the payer force-closes the channel. With this test we
demonstrate two bugs in our handling of hold invoice state
in the invoice registry when we expire on chain:
- Htlcs not updated: even when we've timed out, we don't
update the htlc state accordingly.
- Invoice can be settled: the invoice can be settled even
though it's expired on chain.
