[code-cache] Drop checking we increased the age

We might be racing with code that resets the age to 0, causing CAS to
fail (or us to read an already reset value).

Change-Id: I3ba555d64d48c4e2d2399978427c764c0e6e7128
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3735167


Auto-Submit: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81445}