Merge pull request #1957 from TheBlueMatt/2022-01-mon-ref-lockorder

Pass MonitorUpdates by ref and tweak manager lockorder

diff --cc fuzz/src/chanmon_consistency.rs
Simple merge

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

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

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

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