Changed a function in the internal debugger JavaScript to return the full source location instead of only the position.

Added an optional parameter to exclude/include the source line offset in source location.

Extended a message test to include a test with source offset.
Review URL: http://codereview.chromium.org/39342

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@1461 ce2b1a6d-e550-0410-aec6-3dcde31c8c00