In 2019, Jorn added that all `final` fields in classes that reside in the `java.lang` packages are trusted fields in the class `ciFields.cpp`. This would allow us to remove some of the previous checks as they are already covered by the package check.

The package check is: holder->is_in_package("java/lang"))

In addition, the untrusted fields in java.lang.System are all static fields. The special rule for java.lang.System is never useful because it has no untrusted instance field; furthermore, the problematic static fields are already checked before trust_final_non_static_fields is called.

So we should remove:
1. java_lang_System check
2. is_box_klass check
3. java_lang_String check