This switches Isolate::ComputeLocation to use baseline code when
computing message locations. This unifies locations between optimized
and non-optimized code by always going through the FrameSummary for
location computation.

R=bmeurer@chromium.org
TEST=message/regress/regress-4266
BUG=v8:4266
LOG=n

Review URL: https://codereview.chromium.org/1331603002

Cr-Commit-Position: refs/heads/master@{#30635}