Pending exceptions were not cleared when the TurboFan result was not
compared to the Interpreter result, which happens when the result may be
affected by potential nondeterminism. With this CL we always clear
pending exceptions.

R=clemensh@chromium.org

Bug: chromium:782267
Change-Id: Ibe9b33c94810cccb6282c6c8dc49748fb79b07e4
Reviewed-on: https://chromium-review.googlesource.com/758272Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49265}