That warning about missing data was sometimes printed even
when nothing was missing.

(Also drop an outdated TODO.)

Bug: v8:7790
Change-Id: I9550b3237c87b7b0e59f740c34b13d3e38d8d36e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1917153
Commit-Queue: Georg Neis <neis@chromium.org>
Auto-Submit: Georg Neis <neis@chromium.org>
Reviewed-by: Maya Lekova <mslekova@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65010}