Remove expired histograms in BlockFiles

These are no longer used.

Bug: 1448182
Change-Id: I535e19224ce886ff3fa1296bb9137da03dc7125b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4564175


Commit-Queue: Kenichi Ishibashi <bashi@chromium.org>
Reviewed-by: Nidhi Jaju <nidhijaju@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1148917}