SI-8151 Remove -Yself-in-annots and associated implementation

This experimental option typechecked arguments of annotations
with an injected value in scope named `self`:

    @Foo(self.foo < 1)

This has been slated for removal [1] for some time.

This commit removes it in one fell swoop, without any attempt
at source compatibility with code that constructs or pattern
matches on AnnotatedType.

[1] https://groups.google.com/d/msg/scala-internals/VdZ5UJwQFGI/C6tZ493Yxx4J