Issue #1221: test: Add something really basic.
Issue #1221: test: Add CollidingLiteralDefaults which demonstrates a problem with how we were naming the constants used when annotation constructors had literal arguments for defaulted parameters.
Issue #1221: Rewrite a lot of how we handle annotation constructors and annotation instantiation.

* Move the 'annotation model' and the visitor which built it from ceylon-spec and into the compiler (where it's actually used)
* Rewrite this to support annotation constructor and class invocation in defaulted parameter expressions and as arguments to the annotation class in the annotation constructor body.
* Run the AnnotationModelVisitor as part of codegen instead of during typechecking, since it now generate some JCTree nodes.
* Support emitting @AnnotationInstantiation on defaulted parameter methods, when the defaulted parameter is an annotation class or constructor invocation, as described in #1221
* Support emitting @AnnotationInstantiationTree as a way of serializing a tree of invocations in the body of an annotation constructor, as described in #1221
* Rewrite the AnnotationInvocationVisitor to use the revised annotation model
Issue #1221: Fix tests now that constant names distinguish between the default and literal argument cases.
Issue #1221: Start fixing the model loader to understand the new model better.
Issue #1221: Pass along the expected type for constant fields, since it matters, apparently.
Issue #1221: test: Split Nested test into two one for the annotation classes and constructors and one for the callsite, so I can test model loading.
Issue #1221: Fix model loading from @AnnotationInstantiation and @AnnotationInstantiationTree.
Issue #1221: test: Fix Nested.src because the annotationClass member of @AnnotationInstantiation can now be an annotation constructor as well as an annotation class.
Issue #1221: Changes for renaming of @AnnotationInstantiation.annotationClass() -> primary()
Issue #1221: .src fixes for renaming of @AnnotationInstantiation.annotationClass() -> primary()
Issue #1140: Declaration literals in annotations.
Issue #1140: test: Improve the AnnotationClassMetamodelReference test.
Issue #1140: test: AnnotationClassMetamodelReference: Enable an annotation constructor that now compiles.
tests: Reinstate some commented-out parts of AnnotationClassMetamodelReference
annotations: Add VariadicTricks test.
AnnotationInvocationVisitor: Fix for VariadicTricks.
test: Add final to annotation class in the metamodel tests
test: Add final to annotation class in the metamodel tests
test: MetamodelTest: Fix an expected error message, which I assume has been changed.