[PMC] Take better advantage of parent's GC behavior.
[PMC] Take better advantage of parent's GC behavior.

Don't poke in the guts of other subs during destruction.  That's naughty, and
removing it appears to have fixed a Lua segfault as well as the shootout 16
problem for me.  Let those subs clean up after themselves.

Minor formatting cleanups.

git-svn-id: 6e74a02f85675cec270f5d931b0f6998666294a3@20843 d31e2699-5ff4-0310-a27c-f18f2fbe73fe

ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot