389678: Better support for overweaving

389678: Better support for overweaving

More testcases for overweaving and better handling of WeaverStateInfo
to avoid the dreaded problems deserialized the 'special key' used
to store diffs.

With these changes once a class is woven via overweaving we switch
the diff we store in the weaverstateinfo to 0 byte array (indicating
overweaving happened for later weavers that see it). We also stop
writing the special 'key' into the attribute and avoid looking-for
and attempting to replace it at the end of weaving.