* tka.State.staticValidateCheckpoint could call methods on a contained key prior to calling StaticValidate on that key
* Remove broken backoff / RPC retry logic from tka methods in ipn/ipnlocal, to be fixed at a later time
* Fix NetworkLockModify() which would attempt to take b.mu twice and deadlock, remove now-unused dependence on netmap
* Add methods on ipnlocal.LocalBackend to be used in integration tests
* Use TAILSCALE_USE_WIP_CODE as the feature flag so it can be manipulated in tests
Signed-off-by: Tom DNetto <tom@tailscale.com>
