* Initialize the diganostics logger with opts.Debug when doing
a Deploy, like we do Plan.
* Don't spew leaked promises if there were Log.errors.
* Serialize logging RPC calls so that they can't appear out of order.
* Print stack traces in more places and, in particular, remember
the original context for any errors that may occur asynchronously,
like resource registration and calls to mapValue.
* Include origin stack traces generally in more error messages.
* Add some more mapValue test cases.
* Only undefined-propagate mapValue values during dry-runs.
f9995159c6