This changes "d8" to no longer report exceptions as being "caught" when
it comes to the catch prediction mechanism in our debugger. This treats
scripts as being truly top-level when it comes to exception handling and
will allow us to properly test the catch prediction mechanism using just
mjsunit tests alone.

R=yangguo@chromium.org
BUG=v8:4674
LOG=n

Review URL: https://codereview.chromium.org/1691723002

Cr-Commit-Position: refs/heads/master@{#33898}