* Bump to Xcode 9 beta 2
* [CoreImage] Stub out new CIImage filters in Xcode 9 beta 2.
* [monotouch-test] Update tests according to Xcode 9 beta 2.
* [xharness] Ask watch simulator tests to write output directly to a file.
It seems the watch simulator in Xcode 9 beta 2 has completely lost network
access (everything times out), so instead ask the tests to store results
directly in the resulting file.
This works for now since the watch simulator does not enforce the sandbox.
* [xharness] Rewrite the logic to write unit output to a file so that it works with Jenkins.
For Jenkins we ask the unit tests to produce XML, and this needs some special
treatment.
* [xharness] Protect against exceptions in the listener thread, so that it doesn't take xharness down.
* [xharness] Protect against a potential NullReferenceException, and fix one case where it would occur.
* [xharness] A few logging fixes.
* [Intents] Fix API & tests according to beta 2 changes.
Vincent Dondain