FSA: Consolidate move() and rename() to just move()

Bug: 1263262
Change-Id: I9dc08c8e1783bc5ab51d1a91c76b15f6a1c8eab0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3257898


Auto-Submit: Austin Sullivan <asully@chromium.org>
Reviewed-by: Marijn Kruisselbrink <mek@chromium.org>
Commit-Queue: Austin Sullivan <asully@chromium.org>
Cr-Commit-Position: refs/heads/main@{#958140}