Jaxb2Marshaller doesn't need to depend on ResourceLoaderAware

Issue: SPR-10512
Compatibility of JDK 8 compiled reflection API usage with JDK <8 runtimes

Specifically, we need to avoid "... ? this.method : this.constructor" expressions since those potentially select java.lang.reflect.Executable (which is only available on JDK 8) as common type and hardcode this into the generated bytecode (which therefore becomes JDK 8 dependent).