PMC: add tests for ResizableStringArray PMC ~ shift/unshift ~ stress tests ~ sparse access
PMC: add tests for ResizableStringArray PMC
~ shift/unshift
~ stress tests
~ sparse access

git-svn-id: 6e74a02f85675cec270f5d931b0f6998666294a3@11144 d31e2699-5ff4-0310-a27c-f18f2fbe73fe

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