Merge pull request #1481 from TheBlueMatt/2022-05-new-chain-tests

Test coverage for `transaction_unconfirmed`

diff --cc lightning/src/ln/chanmon_update_fail_tests.rs
Simple merge

diff --cc lightning/src/ln/functional_test_utils.rs
Simple merge

diff --cc lightning/src/ln/functional_tests.rs
Simple merge

diff --cc lightning/src/ln/payment_tests.rs
Simple merge

diff --cc lightning/src/ln/reorg_tests.rs
Simple merge

diff --cc lightning/src/util/test_utils.rs
Simple merge