Pass ChiselCircuitAnnotation through CIRCT phase (#3016)

Cause the ChiselCircuitAnnotation (which is Unserializable and will be
dropped) to be passed through the CIRCT phase.  This is necessary to
enable certain D/I use cases where an ImportDefinitionAnnotation is
constructed from a ChiselCircuitAnnotation returned from a prior
ChiselStage invocation.

Signed-off-by: Schuyler Eldridge <schuyler.eldridge@sifive.com>