[JExtract/JNI] Omit unsupported types instead of crashing

[madsodgaard]

Omits any unsupported types such as UInt8 instead of crashing the generation.

[ktoso]

Minor log level nitpick.

Does the FFM mode already do the same? Can we add the same “test” (just a decl we ignore) in FFM?

[madsodgaard]

@ktoso Yes FFM should also ignore any unsupported types, but I also added a unsupported type to the FFM sample app.