We allocate console timing messages for now,
as previously skipping this tickled unrelated flake.
Use a fixed message to make them consistent in predictable mode.

BUG=v8:4203
TBR=titzer@chromium.org

Review-Url: https://codereview.chromium.org/2628173003
Cr-Commit-Position: refs/heads/master@{#42303}