Streamline AbstractInterpreter::method_kind

This method checks m->intrinsic_id() in three different places, which instrumenting shows end up in different branches. Some of that split is due StrictMath having one method that is both native and an @IntrinsicCandidate.

It would be simpler - and slightly more efficient - to streamline this and deal with the exceptions on a case by case basis.

On a Hello World, a streamlined method_kind implementation is roughly 40% faster - adding up to a 0.25% reduction in instructions executed. This is called when linking methods, so the gain scales with application size.