Merge latest d16-2 into xcode11 (#6766)

* [tests] Handle Xcodes without proper versions by ignoring them. Fixes xamarin/maccore#1768. (#6386)

This can happen if an Xcode hasn't been completely/successfully installed or
removed.

Fixes https://github.com/xamarin/maccore/issues/1768.

* [CoreGraphics] Fix lifetime of delegates passed to CGPatternCreate. (#6368)

We may get callbacks after the managed CGPattern instance has been
disposed/garbage collected, so make sure our delegates survives that long.

Since the delegates don't need any instance state, just make them static.

* [d16-2] Bump mono to pick tz/DST fixes.. (#6454)

* [xharness] Don't try to find simulators for ignored tests. (#6421)

Trying to find a simulator will mark the test as a failure if the simulator
couldn't be found, and we don't want that to happen to ignored tests.

This should fix an issue where xharness seems to try to run the 32-bit
simulator tests when asked to run only device tests.

* [tests] Only call MTLDevice.CreateSharedTexture macOS 10.14+. Fixes xamarin/maccore#1663. (#6423)

Fixes https://github.com/xamarin/maccore/issues/1663.

* [d16-2] [GameController] GCGamepad is deprecated in the headers, so mark it as such. Fixes xamarin/maccore#1742. (#6428)

* [GameController] GCGamepad is deprecated in the headers, so mark it as such. Fixes xamarin/maccore#1742.

Fixes https://github.com/xamarin/maccore/issues/1742.

* Add attribute for tvOS too.

* [package] Remove creation of files/symlinks under /Developer (#6665)

* [d16-2] [tests] wrench is long gone (#6698)

* [tests] wrench is long gone

* Use a different Url that works and ensure we get a nice message when we have a failure.

* Fix new callback test.

* Ignore the outgenerated projects until they are moved to their own dir. (#6714)

Related issue #6162