This is dead code, so should be removed.

JDK images can be built with it removed and there's no evidence of call sites (either via JNI or cpp) anywhere in the code (and there were no tests for it).

The benefit of removing this is reducing the number of places where the flags associated with package references are used, since those flags can be adapted/extended to make preview mode support easy.

So having one fewer places that read them is good.

This will be trivial to integrate across into mainline later.