Add a test that const declarations are recognized as having side-
effects in REPL mode.

Bug: chromium:1043151
Change-Id: I6f8038ab4a5ee446d23904ed46637223157db5c7
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2013114Reviewed-by: Simon Zünd <szuend@chromium.org>
Commit-Queue: Peter Marshall <petermarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65916}