This issue tracks some implementation clean up issues for hidden classes in the nestmates branch.

1. rename "is_nonfindable" to "is_hidden"
2. the name of the hidden class is assigned by the VM (Klass::external_name)

    The name parameter in JVM_LookupDefineClass is simply a binary name that can be used by the VM as a prefix but not guaranteed to be unique. The VM appends the name with "/" and unique id (address of the klass in the implementation) to follow the long-standing convention of Unsafe VM anonymous class.

The name of `this_class` in the CP entry should be re-examined if it should be set to a sentinel value or NULL.

3. define struct ClassLoadInfo to wire all random bits in one place (something like bootstrapInfo.hpp) (see JDK-8230816)

4. It may be useful to augment VM logging to show other properties when a hidden class is created (e.g. weak or nest host or etc)