Under --print-all-exceptions, it's possible for the script
Get(Line|Column)Number functions to trigger a GC. This is noted in the
function, however there is a raw exception Object* which is live across
these calls, and whose object could be moved by the GC.

Now the pointer is reloaded from a handle to the exception object.

Change-Id: I81a26aebfc983199edc97374242c898131d52934
Reviewed-on: https://chromium-review.googlesource.com/1101031
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53749}