This adds support to the deoptimizer to materialize ContextExtension
objects that have been de-materialized by escape analysis. This is
follow-up to the inline allocation of such objects during the create
lowering phase (i.e. JSCreateWithContext and JSCreateCatchContext).

R=bmeurer@chromium.org
TEST=mjsunit/regress/regress-crbug-644245
BUG=chromium:644245

Review-Url: https://codereview.chromium.org/2317353003
Cr-Commit-Position: refs/heads/master@{#39270}