Cleanup of http://codereview.chromium.org/8101.

Cleanup of http://codereview.chromium.org/8101.

Changed the catcher_ field to a boolean value and renamed it. Modified the
propagation of the external caught exception to also clear the current
TryCatch if there is no exception as it might hold an exception which has
been bypassed by code in a finally block.

Minor formatting changes to a test.
Review URL: http://codereview.chromium.org/8102

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@576 ce2b1a6d-e550-0410-aec6-3dcde31c8c00