Never class-load `TurbineProcessingEnvironment` from the `-processor`
Never class-load `TurbineProcessingEnvironment` from the `-processor`

since it gives dagger access to an internal API, to avoid skew if turbine
is on the `-processorpath`.

Continue to only do classloader masking for other APIs if the built-in
annotation processor features are enabled.

Follow-up to https://github.com/google/turbine/commit/3bbf96736b45e2450d41b4ee1ca355402ef3f46d

PiperOrigin-RevId: 374933572

google/turbine