With --harmony-sloppy we can get to a runtime store in the presence of
an eval. We therefor need to check that the value is not the hole which
is used to enforce TDZ.

BUG=v8:4284
LOG=N
R=rossberg@chromium.org, littledan@chromium.org

Review URL: https://codereview.chromium.org/1214733013

Cr-Commit-Position: refs/heads/master@{#29577}