Also add a configuration switch to disable the codegen, so we can
still use the metadata emit and tsickle pre-processing in the
build pipeline for angular itself.
Before, we would create all fields in the generated views
with visibility `private`. This does not work if an embedded
view references a directive / element in a parent view.
In Dart, this was no problem so far as it does not have
a `private` modifier.
Before, `useValue` in a provider did not work when doing
offline compile, as so far the `MetadataResolver` was only
used for jit mode. Now, `useValue` supports any kind of value
that the static reflector can return. E.g. primitives,
arrays, string maps, …
Closes#8366