- part 1/2 of #2294
- handle readonly non-`null` collections in relevant binders
- `CollectionModelBinder.CopyToModel()` and `MutableObjectModelBinder.AddToProperty()` methods
- handle read-only controller properties in `DefaultControllerActionArgumentBinder`
- do not copy into arrays e.g. add `CopyToModel()` override in `ArrayModelBinder`
- remove ability to set a private controller property
- confirm `SetMethod.IsPublic` in `DefaultControllerActionArgumentBinder`
- avoid NREs in `GetModel()` overrides
Test handling of readonly collections
- previous tests barely touched this scenario
- also add more tests setting controller properties
nits:
- add missing `[NotNull]` attributes
- add missing doc comments
- consolidate a few `[Fact]`s into `[Theory]`s
- simplify some wrapping; shorten a few lines
- remove dead code in `DefaultControllerActionArgumentBinder` and `ControllerActionArgumentBinderTests`
3fd4991959