remove Isolate::Current from most files starting with 'j' through 'o'

R=bmeurer@chromium.org
BUG=

Review URL: https://codereview.chromium.org/23578012

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@16520 ce2b1a6d-e550-0410-aec6-3dcde31c8c00